The Aberporth site sits in a stunning cliff top location, show below in another exclusive bird's eye view from my contributor with a pilot's licence! It was once called DTEO Aberporth - the Defence Test and Evaluation Organisation, a forerunner of DERA. On some maps, DTEO Aberporth is labelled "T & EE" - Test and Evaluation Establishment. It is known to be involved in research and development of Doppler effect pulse radar.

The Llanbedr site was an operational airfield, formerly designated the Royal Aerospace Establishment, from which target drones were launched. QinetiQ suspended operations at Llanbedr in late 2004 and formally handed the base over to Defence Estates for disposal in early 2005, with the loss of almost 150 jobs.

Newer target drones, not requiring a runway for take-off, will now be launched from the existing facilities at Aberporth. Whilst the future of Llanbedr's airfield is currently uncertain, such a valuable asset will surely not remain idle for too long.

The Isle of Anglesey is world famous for the village name that at 58 letters, is as long as the trains stopping at its station. It is usually abbreviated by tourists to "Llanfair PG" and the Royal Mail manages "Llanfairpwllgwyngyll".

Perhaps less well known is that the MoD maintains the HQ of the Joint Services Mountain Training School (JSMTC) here at Plas Llanfair, under the shadow of the Britannia Bridge across the Menai Strait. The facility is also referred to as "Defatigable". Not surprisingly, small outposts of the JSMTC (called Wings - JSMTW) can be found in the Scottish Highlands at Ballachulish near Glencoe, at Dundonnell near Ullapool and next to Tulloch Station near Spean Bridge and Fort William, but also at Deverell Barracks in Ripon, North Yorkshire.

In North Wales, in the centre of the village of Llanrwst near Betws-y-Coed, you'll find the Joint School of Adventurous Training Instructors (JSATI) . On a connected theme, the Joint Services Adventurous Sail Training Centre (JSASTC) is down near Portsmouth Naval Base at Haslar Marina.

The buildings are merely empty houses with no residents and no outside visitors. What's going on? Is it perhaps an exterior film set for another reality TV show? No, the numerous houses are for use by the Army's FIBUA teams – Fighting In Built-Up Areas. A rather more politically correct term is OBUA – Operations in Built-up Areas – although army wags have been known to refer to it all as FISH & CHIPS – Fighting in Someone's House and Causing Havoc in People's Streets! Special villages like this are used by soldiers undergoing vital Operational Training and Advisory Group (OPTAG) courses, before being deployed to war zones. The equivalent US military terms for FIBUA / OBUA are UO (Urban Operations) and MOUT (Military Operations in Urban Terrain).

In Sennybridge, in traditional SAS country, special training in CQB – Close Quarters Battle – takes place. Zoom into the 1:10000 map from the MAGIC website and the mysterious village around the farm is helpfully labelled "Mock Township (Army Training Area)".

In Scotland, a FIBUA / OBUA centre can be found near Faslane nuclear submarine base, at Strone Camp at the southern end of the Garelochhead training area. The "depot" at Strone within the forest clearing is actually the old Admiralty Hydroballistics Research Establishment. The main Garelochhead training area's military camp is 2km to the west. It is in the middle of several fuel storage depots and is visible through the trees from the adjacent train line.

In England, other FIBUA / OBUA facilities can be found on Salisbury Plain at Copehill Down near Shrewton in Wiltshire and at the urban warfare mock-up village at Eastmere , adjoining West Tofts Camp near Thetford, Norfolk within the Stanford Training Area (STANTA). More can be revealed at the Army's major training camps at Whinny Hill (sometimes spelt Whinney) at Catterick, in North Yorkshire and at Lydd Ranges near Dungeness Nuclear Power Station in Kent. Just a little east along the Dungeness coastline at Hythe Ranges you can spot yet another FIBUA village. The posters of Saddam Hussain and a fake shop sign reading "Abdul's Cafe", reveal that training for deployment in Iraq and Afghanistan has occurred here!

There are additional FIBUA / OBUA facilities at the south end of Longmoor Camp near Bordon in Hampshire (which use the old married quarters) and at the disused Sherfield Farm deep within the Bramley Training Area near Basingstoke, which is clearer on MAGIC's 1:10000 scale map. The Copehill Down aerial photo, plus ground photos of the Longmoor Urban Training Complex (UTC) and Bramley Training Area, can be found on the MoD Film and TV locations website:-

• www.mod.uk/DefenceInternet/AboutDefence/WhatWeDo/DefenceEstateandEnvironment/MODFilmLocations/
  SouthWest/CopehillVillage.htm
• www.mod.uk/DefenceInternet/AboutDefence/WhatWeDo/DefenceEstateandEnvironment/MODFilmLocations/
  South/LongmoorUrbanTrainingComplex.htm
• www.mod.uk/DefenceInternet/AboutDefence/WhatWeDo/DefenceEstateandEnvironment/MODFilmLocations/
  South/BramleyBuildings.htm

In August 2008, special council planning permission was granted for an £18 million transformation of the West Tofts / STANTA facilities. The Eastmere FIBUA village was extended and radically redesigned as a Middle East urban town including a factory. Meanwhile, a brand new Middle Eastern rural village, including a mosque and market stalls, has been constructed over near Stanford village itself at Bridge Carr within Buckenham Tofts Park. In particular, mock-ups of Afghan village houses incorporating Taliban "murder holes" and quick escape routes have been built. It was officially opened in May 2009. Click here to see the graphic overlay shown below within context on Google Earth.

Whilst the B-2's home base (since December 1993) is Whiteman AFB in Johnson, Missouri, US, these important developments at RAF Fairford since 2004 will provide the opportunity of forward deployment of the B-2 Bomber within the UK.

Other established locations are at Andersen AFB on Guam in the Pacific Ocean and at Diego Garcia AFB in the Indian Ocean (where four LO Docks are already situated).

Furthermore, two replicas of the Whiteman AFB B-2 Bomber permanent hangars have been constructed next to the new fuel depot at RAF Fairford's north east side, where some old buildings have been demolished.

All of these improvements to Fairford were put to the test in August 2008 when a top secret training mission was conducted. Excited plane spotters were feverishly typing "B-2 Stealth in skies over UK" into Google for many days, but the truth was only released after the radar avoiding plane was safely back home.

Squadron Leader John "Killer" Killerby flew his B-2 all the way to the UK from its base at Whiteman AFB. He had joined the elite B-2 team from his original posting flying Tornados with 14 Sqn at RAF Lossiemouth in Scotland. He dropped a payload of ordnance over Lincolnshire – but it was the famous military test range at Wainfleet, not the historic cathedral city! After the successful sortie, the stealth bomber then landed at Fairford to have its secret coating "tweaked" before returning to base.

During 2007, Google Earth watchers noticed a mural of a B-2 Bomber painted on the bottom of a swimming pool at Whiteman AFB (further below), but by June 2007 it had mysteriously disappeared. The explanation? Another imagery update had been performed and this time, the pool was filled with water thereby making the mural impossible to see!

A real B-2 Bomber can be spotted manoeuvring around Whiteman AFB (also further below) on a black and white snapshot taken on 8th March 1997 by the US Geological Survey (USGS) as part of their National Aerial Photography Programme (1987 - present). In early 2008, Yahoo Maps was featuring differently sourced aerial photography (from I-cubed) showing another B-2 in a similar position near its hangar!

Fairford's weapons facility at RAF Welford only returned to OS maps very recently, following decades of the "airbrushing" treatment! You can make out the original paths of the runways on the aerial photo, which also clearly shows the racks of munitions.

Note the nearby presence of a disused railway line . This was the method of munitions transportation in the 1960s and before. A fascinating pictorial history of the construction of the military branch line from the former Welford Park Station can be found on Ken Tarbox's comprehensive Lambourn Valley Railway website.

• www.lambournvalleyrailway.co.uk/pages/welfordairbase/airbase.htm

The site (pictured further below in exclusive Pilot's Eye views shot in 2007) is so important that it has its own slip roads connected to the east-bound carriageway of the nearby M4 motorway! Commuters travelling into London every day from the west, will drive past an exit marked "Works Unit Only". It's between Junctions 13 and 14. I suppose Harry Potter would call it Junction 13½!

The fact that the "Works Access Only" sign is in red gives the game away really. All UK military establishments are signposted this way. The two slip roads were constructed in the mid 1980s and were financed by the USAF to the tune of £377,000.

There seems to be another "secret" junction on the M4 further west. To find out more, read on!

Another large munitions base, similar to Welford, is situated just north of the M48 motorway in South Wales at Defence Munitions (DM) Caerwent in Gwent (above), although this site is now supposedly just used as an Army "training area".

The last remaining UK Royal Ordnance Factory still in operation was actually missing from all maps until the 1990s. It is also in South Wales but just over the county border in Monmouthshire. Now part of BAe Systems, ROF Glascoed between Usk and Pontypool can be found on all OS mapping data.

Yet another munitions depot, DM Dean Hill, near the village of West Dean in Wiltshire - only recently decommissioned - didn't feature on any maps, until November 2004! Suddenly, Get-a-map's 1:25000 OS map was revised to show the depot, but it remained invisible at 1:50000 scale! Then in 2005, the 1:50000 data was suddenly updated to show the full detail too!

Before those revisions, in order to finally get at the truth, you needed to go to Multimap's aerial photo. Most of the DM Dean Hill site is, in fact, underground. The DM Dean Hill site at West Dean is pictured below in a special bird's eye view, my contributor with a private pilot's licence! Check out his other amazing photos in the other parts of Secret Bases!

After the delights of Dean Hill, it's "chocks away" again and we're off down to the south west tip of Wales for another Pilot's Eye trip to the old wartime Royal Naval Armaments Depot (RNAD) at Trecwn near Fishguard, Pembrokeshire.

This old WWII Navy munitions storage base, dating from the late 1930s, is laid out along the full length of a valley floor and was served by a main train line into a marshalling yard, then into transfer sheds and onto a narrow gauge track system. It was taken over in 2003 by The Valley (Pembrokeshire) Limited, a company which is transforming the whole site into a business park and devoting many bunkers to the storage of high value property and data for clients.

Take a look at my exclusive aerial surveys taken in April 2007 further below, from my regular specialist contributor. Starting at Trecwn village in the west, you'll see the main depot , together with transfer sheds, then an eastern curve which suddenly takes us north to some bunkers hidden in the valley's wooded slopes and finally, almost three miles from the start, the northern end .

Meanwhile, both 1:50000 and 1:25000 maps are sufficient to reveal another remote ordnance depot for the former RAF Chilmark, alongside the main line rail sidings at nearby Dinton, within Fovant Wood . Similarly, on the other side of the train line alongside more sidings, the WWII RAF Baverstock military supply depot can be seen.

RAF Chilmark was decommissioned in 1996, long before this website was even thought of, but in August 2005 the International School for Security and Explosives Education (ISSEE - pronounced "I See") moved into part of the main Chilmark site - what is now the UK Centre for Homeland Security.

The ISSEE relocated from its original base within Tidworth College , appropriately at the end of Ordnance Road, in amongst the numerous military camps over on the other side of Salisbury.

At the new "centre of excellence" at Chilmark, specialist anti-terrorism training and advice will be given to both UK and international government, defence and police departments, etc., using equipment such as aircraft fuselages, train carriages and trucks - presumably similar to the SAS counter-terrorism trainer unit at Pontrilas, discussed elsewhere in Secret Bases.

In fact, the Chilmark facilities sound remarkably like the so-called "Camp Secret" referred to in the Daily Mirror's exclusive story published on 14th September 2006, the location of which they didn't actually reveal! The story kicked off with, "Hidden deep in the heart of the English countryside, is a top secret training camp, which is the nerve centre of the international war on terror."

A company based at the Chilmark camp called Air Robot UK (formerly Rotorcams) develops Unmanned Aerial Vehicles (UAV) which carry high quality video surveillance cameras on board.

• www.issee.co.uk
• www.airrobot-uk.com
• Daily Mirror "Camp Secret" story

The RAF have their Strike Command main HQ at the Buckinghamshire town of High Wycombe. Note the command bunker in the suspicious clearing in Park Wood, carved out of the Chiltern Hills! Incidentally, the RAF Personnel and Training Command at RAF Innsworth , Gloucestershire is due to be relocated here in the next few years. It's the place to go to when you're searching for wartime RAF records.

Another command bunker can be found at RAF Daws Hill on the other side of High Wycombe. This installation is a former US Cold War HQ for operations in Europe. Staff in the bunker would have launched Cruise Missiles. In the 1980s, walkers reported that the ground underneath Daws Hill would actually hum and buzz with activity! More recently the base has acted as a storage depot for the US Navy.

One famous underground bunker site at the south end of Peel Circus, off Park Lane in Corsham is referred to simply as the Corsham Computer Centre (or "CCC"). It is on highly secure ring-fenced land bounded by old tracks (St. Barbara's Road and Paddock Lane) but is now also adjacent to two brand new housing developments to the north and east, around Pockeredge Farm. It is a "black project" – it has never been approved by or even discussed in Parliament ... until March 2007, that is!

It has been suggested as the Government's new backup seat of control in the event of a national emergency. Such as nuclear war! The official line (and possible cover story) is that the CCC is merely a Royal Navy administration centre. The truth was always likely to be somewhere in the middle and pointed towards the CCC being a major military command, control, communications and monitoring facility for all the UK armed services – maybe even NATO.

In March 2007, I discovered that some fascinating written evidence from the Scottish Campaign for Nuclear Disarmament (Scottish CND, SCND), submitted to the Select Committee on Defence, had been published on the UK Parliament's official website. It formed part of the Select Committee's Ninth Report of the House of Commons 2006/2007 Session, "The Future of the UK's Strategic Nuclear Deterrent: the White Paper".

In the SCND evidence, submitted in January 2007, the CCC was described as the place where work on the computer software for Trident submarines is carried out by a major defence contractor called MASS Consultants Limited.

The acronym MASS was derived from "Mathematical and Associated Scientific Services" and the company was formed in 1983 by former BAe Systems staff. It was bought by the Cohort group in July 2006 for £12.5 million. In Cohort's press release at that time, announcing the acquisition, it boasted that MASS Consultants had secured a £43 million ten-year contract in 2000, "to support a highly secure Ministry of Defence Computer Centre". It continued, "The scope of work includes systems modelling, IT maintenance and support, operational analysis, software development and team management". In 2010, MASS acquired Abacus Electronic Warfare Consultancy and now trades that under the name MASS-Abacus from within Wellingore Hall .

Cohort plc is based at The Court House in Henley-on-Thames, Oxfordshire, where their other major defence contractor SCS (Systems Consultants Services) Limited also has its main offices. Yet another Cohort company based there – a division of SCS – operated as Advanced Geospatial Solutions Limited (AGS) and specialised in 3D visualisation software, until it ceased trading in August 2009. It had close connections with Lockheed Martin. Another 3D software specialist Cunning Running has now taken on the AGS product range.

MASS Consultants have their headquarters at Enterprise House in the village of Little Paxton just north of St. Neots in Cambridgeshire. Their technical base for Electronic Warfare (EW) and Information Technology (IT) software development is in a brand new industrial unit next to the Renault car dealership on Tritton Road, to the south west of Lincoln. It is no accident that the Lincoln MASS base is so close to RAF Waddington's new Defence Electronic Warfare Centre (DEWC) – their other major project client. Both are shown in Bird's Eye aerial photos from Windows Live Local further below.

The Parliamentary document states that MASS Consultants manage the IT system within the underground computer centre in Corsham, on behalf of the MoD's Strategic Systems Integrated Project Team (StratSys IPT). It goes on to state that analysts who assess the performance and effectiveness of Trident use the IT facilities in the centre.

Furthermore, it reveals that the trajectories of Submarine Launched Ballistic Missiles (SLBM) are analysed by a company called INSYS (formerly Hunting Engineering), which has now been acquired by Lockheed Martin UK. The Lockheed Martin INSYS site can be found within Reddings Wood at Ampthill in Bedfordshire, marked on OS maps with that favourite label "Works"!

The document offers an alternative, official, but rather dull name for the CCC – the Corsham Software Facility – and it is widely known that it appears on suppliers' invoices as simply "Corsham Computers".

On the website of the MoD's Acquisition Management System (AMS), I found a non-classified document buried away in an annexe to the Defence Supply Chain Manual ("JSP 336", 3rd Edition, September 2006). It is a list of Trident customers and their Unit Identification Numbers (UIN). The final entry on that list reads "Corsham Computer Centre", alongside a UIN of "P0550H".

Furthermore, in September 2007 a press release by Babcock Infrastructure Services made specific reference to the Corsham Computer Centre. Babcock was cock-a-hoop at winning a £45 million three-year contract from December 2007 (with options to extend to six years). It covers the provision of facilities management services for the CCC, plus various other defence sites around Bath and Bristol involving over 10,000 MoD personnel. The contract was awarded to Debut Services Limited – a Babcock company in joint venture partnership with Bovis Lend Lease.

It is interesting to note that the name "CCC" is also widely used in military circles to refer to "Command, Control and Communications", which is nowadays formed into the snappier acronym "C3". Then there's "C3I" with "Intelligence" appended and even "C4I", with the added ingredient "Computers". It is hardly surprising that MASS, SCS and Cohort all specialise in these key project areas.

The CCC was built within Hudswell Quarry (just north of Tunnel Quarry), next door to Basil Hill Barracks and has been persistently rumoured to be powered by a nuclear generator and contain vast American number-crunching mainframe supercomputers. Even more astonishingly, it has been alleged that the Royal Family and the Government's top brass can be evacuated from London by train direct to the CCC by a secret link inside Box Tunnel.

The "secret link" story simply originated from the wartime ammunition supply rail line down into Tunnel Quarry complete with dedicated loading platforms. The external door into the abandoned underground ordnance depot can still be seen at Box Tunnel's eastern approach, adjacent to the main train line.

Amazingly, the CCC is even fully listed on Royal Mail's address database with a unique postcode, not shared with any other street or building. The entry helpfully reads,Experiment for yourself and try typing that postcode into Get-a-map, Multimap and Streetmap. Using the postcode on the Getmapping site shows an aerial photo centred perfectly on the bunker blast door entrance. Since Summer 2007, Corsham has been available at hi-res on Google Earth too!

• HC 225 – "The Future of the UK's Strategic Nuclear Deterrent: the White Paper"
  Defence Select Committee's Ninth Report of the House of Commons 2006/2007 Session
  Volume I (Full Report) and Volume II (Submitted Evidence) – Published 7th March 2007
• www.publications.parliament.uk/pa/cm200607/cmselect/cmdfence/225/225we06.htm
  [Volume II: Scottish CND written evidence for report, HTML]
• www.publications.parliament.uk/pa/cm200607/cmselect/cmdfence/225/225ii.pdf
  [Volume II: All evidence for report, PDF]    (Pages 98 through 101, or search for "Corsham")
• www.publications.parliament.uk/pa/cm200607/cmselect/cmdfence/225/225i.pdf
  [Volume I: Full Report, PDF]
• JSP 336 – Defence Supply Chain Manual (3rd Edition, September 2006)
• List of Trident customers, naming Corsham Computer Centre, PDF

RAF Rudloe Manor (south site) contains all the key entrances to the much talked about "Burlington" bunker from the 1950s - a once "top secret" underground city, spread out underneath Corsham and maintained as an emergency Cold War command centre for use in the event of a nuclear strike. Since the original construction, successive Governments have tried to throw inquisitors off the scent by regularly changing its code name – "Subterfuge", "Stockwell", "Burlington", "Turnstile", "Chanticleer", "Peripheral", "Eyeglass" and then just plain old "Site 3"!

In December 2005, the Government finally officially decommissioned Burlington and the BBC were given full (wellalmost full!) access with their cameras. Visit a fascinating interactive tour of the labyrinths beneath Corsham on the BBC Wiltshire website.

Then take a look at the tell-tale surface features within RAF Rudloe Manor, on either side of Corsham's Westwells Road and Old Shaft Road, Live Local's close-up view of Getmapping's aerial photography. Use my special graphic overlays to reveal all those Burlington Bunker clues at ground level: two escalator shafts, two passenger lifts and a goods lift. One of the Burlington passenger lifts is visible, as a huge grass covered mound, from the Rudloe Manor perimeter fence on Westwells Road. Look out for various circular mounds too – they are the all important air intakes and exhaust vents for the plant machinery, kitchens and bakery down below.

Check the interactive map on the BBC website and see if you can match all the surface features to the internal bunker layout! Better still, consult the formerly top secret plans (further below), now officially declassified, obtained through a Freedom of Information request!

After ten years of planning and negotiations, in 2009 the southern part of RAF Rudloe Manor above ground was developed by Ark Continuity into the first phase of their Spring Park Data Centre campus, named after the Spring Quarry beneath, which houses the Burlington Bunker. The first data centre building known as SQ17 is actually built over a Burlington air vent and next to a quarry surface entrance and a service lift shaft. The next phase due to be completed in 2011/2012 will see three more data centres and a plant machinery house – plus underground facilities utilising part of the Spring Quarry tunnels not still owned by the MoD.

Back in Corsham, also notice the presence nearby of RAF Colerne , just north of Corsham, again sometimes referred to as a "disused airfield", but which is actually a key signals analysis unit, formerly 1001 Signals Unit.

Again, Paradigm Services, the company running Oakhanger, also has a Skynet 5 satellite ground terminal presence at Colerne. It is situated within the Azimghur Barracks, adjoining the airfield. Colerne is surely linked to RAF Rudloe Manor, if not also the Corsham Computer Centre. It is also rumoured that the airfield at Colerne may be used to shuttle VIPs in and out of the CCC. Another former Royal Navy Stores Depot can be spotted at a remote corner of the Colerne site.

• www.bbc.co.uk/wiltshire/underground_city/
• www.mod.uk/DefenceInternet/AboutDefence/WhatWeDo/DefenceEstateandEnvironment/MODFilmLocations/SouthWest/
  BurlingtonUndergroundComplex.htm
• www.mod.uk/DefenceInternet/AboutDefence/WhatWeDo/DefenceEstateandEnvironment/MODFilmLocations/SouthWest/
  BurlingtonUndergroundComplexcont.htm
• www.mod.uk/DefenceInternet/AboutDefence/WhatWeDo/DefenceEstateandEnvironment/MODFilmLocations/SouthWest/
  BurlingtonUndergroundComplex3cont.htm
• www.mod.uk/DefenceInternet/AboutDefence/WhatWeDo/DefenceEstateandEnvironment/MODFilmLocations/SouthWest/
  BurlingtonUndergroundComplex4cont.htm

Following the completion of MoD Main Building's major refurbishment in 2004, there was no longer any need for the Metropole building. In October 2004, when I attended the D-Notice Committee Reception (see the Twist in the Tale on my Media Hysteria Page), the Metropole's windows were boarded-up (pictured further below), ready for disposal by Defence Estates. However, quite bizarrely, Room 801 lives on in a song by Dorset Progressive Rockers Galahad who also named their website after the top secret UFO research office in Whitehall!

During 2006, the exterior of the disused Metropole Building, still with its ground floor windows boarded-up, could be seen in several episodes of "Spooks", the BBC's hit series about the exploits of MI5 agents. In one episode, it even posed as the Government's HQ, the Cabinet Office . In reality it is just a little further south west on Whitehall itself, around the corner from 10 Downing Street.

By Spring 2007, the boards had been removed from the windows of the Metropole Building and replaced with warning signs belonging to a private firm of patrolling security guards. In 2010, the Metropole was ready to go full circle and be transformed into the luxury 177,000 sq. ft. Corinthia Hotel, just in time for the anticipated influx of visitors for the 2012 London Olympics! The Corinthia fully opened for business in April 2011.

At the start of WWII, a major heavily fortified command bunker known as the Admiralty Citadel was built just behind (to the west of) the MoD's Old Admiralty Buildings in Horse Guards Parade.

It is still thought to be in use today in some capacity and the ugly ground level entrance building can be seen on the corner of St. James's Park where Horse Guards Road joins The Mall, south west of Admiralty Arch.

On 7th December 1992, a new emergency command bunker code named Pindar was officially opened for business, appropriately underneath the MoD's HQ in Whitehall. It was discussed in detail in Parliament for the first time in April 1994.

Just think: I was merrily enjoying the wine and nibbles at that D-Notice Reception in the historic King Henry VIII Wine Cellar, deep in the basement of MoD Main Building.

Little did I realise that just a few hundred yards away was the entrance to the emergency seat of Government in the event of nuclear war! No wonder all the corridors were being patrolled by guards!

Be sure to visit my Media Hysteria Page to read all about my adventure!

A consortium called Inteq – involving John Laing and Interserve – is the preferred bidder for the project, which is due to get the final go-ahead in late 2007. Interserve will provide on-site facilities management services worth at least £180 million over a 25-year contract period.

The building I originally thought was the GOSCC turns out to be an intriguing facility called "UKNDA - EUDAC". This is the UK National Distribution Agency / European Distribution and Accounting Agency. It handles the secure storage and distribution of cryptographic equipment and material to the UK Armed Forces throughout the world – perhaps even to embassies and SIS (MI6) facilities via the "Diplomatic Bag" system. The previous UKNDA location was at the old MoD storage depot at Kennet Heath, Thatcham, Berkshire – now demolished and replaced by a new housing development.

The original GOSCC location was actually a little to the north west of the UKNDA - EUDAC, but it is now due to be demolished to make way for a vast car park. A replacement GOSCC – yet to feature on Google Earth – is revealed on the Corsham Masterplan blueprint. Also detailed is the new "SLAM" building – the Single Living Accommodation – and the highly sensitive "600 TROOP" building for the Royal Signals Engineers.

Other key buildings are marked "PNCC", "COMCEN" and "EMS", referring to the Primary Network Control Centre, Communications Centre and Electronic Messaging Service.

A famous relic from WWII is preserved too. A curious feature marked "Incline Shaft" turns out to be the Surface Loading Platform for the underground wartime Central Ammunition Depot (CAD), access to which was by the "secret" rail spur in Box Tunnel's eastern portal (pictured further below). The Surface Loading Platform was disguised by some clever camouflaging in the form of a grass covered overhanging canopy!

Was the North Wiltshire Council document release a rare example of brave new "open government" or an embarrassing slip-up? Study the architect's blueprints and decide for yourself!

Before leaving the Corsham area, look out for HMS Royal Arthur - an old Royal Navy leadership training school, which has been in a sorry derelict and vandalised state for a long time, constantly being eyed-up by property developers. Sure enough, there are now plans to turn the site into a vast luxury retirement village of serviced apartments, including a care home. HMS Royal Arthur was previously based in Skegness on the blustery east coast - it occupied Billy Butlin's first holiday camp during WWII.

The DCSA has its main MoD Information Technology support centre, involving huge computer systems, located just off Junction 16 of the M4 motorway in Minerva House on the Delta Office Park in Welton Road, Swindon. Interestingly, this is also the UK Headquarters of the Security Services Group (SSG) which is part of Defence Estates and according to its own website - www.ssg-security.co.uk - is "tasked with the protection of Government, Royal and MoD buildings and sites".

The slip roads don't appear on either 1:50000 or 1:25000 scale OS maps and they don't even get marked on 1:10000 maps from the Government's MAGIC website, which makes them even more suspicious. However, if you have access to Edinburgh University's Edina Digimap system on a higher education campus, you can access Ordnance Survey 1:2500 scale data, giving 10 times the detail of the publicly available 1:25000 series.

As the OS 1:2500 data is obviously commercially sensitive, it cannot be reproduced here for copyright and strict licensing reasons. However, I have produced my own "artist's impression" (further below) to get the message across!

The OS 1:2500 data clearly shows exit slip roads at this point in both east and westbound directions. However, the slip roads are GATED! Moreover, there's a curious "depot" adjacent to the slip roads, on the north side of the eastbound carriageway, which isn't shown on 1:50000, 1:25000 or even 1:10000 scale data.

Note that the path running alongside the south side of the westbound M4 carriageway, shown on 1:50000 maps, is a "red herring". It is an ancient farm track marked on 19th century maps. The new slip roads are hidden in the heavy foliage visible on the aerial photo, hugging the motorway embankments.

All of this understandably got me hot under the collar, so I decided to put the brand new UK Freedom of Information Act (FOIA) to the test! In February 2005, I made a formal application under the Act to the Highways Agency, requesting full disclosure of the details surrounding this "secret" junction. After all, you could see it and touch it so it wasn't too "secret" and yet the public were forbidden from using it. I waited a few weeks and eventually back came the official response.

A Highways Agency spokeswoman told me that the slip roads were constructed in 2003 at a cost of £117,000 and financed from the Highways Agency's local network management schemes economy budget.

The purpose of the slip roads is apparently an "emergency turnaround point" for the Police and other emergency vehicles. When I queried the locked gates, I was told that this was to prevent unauthorised public use and "fly tipping" and that Wiltshire Police carry the keys in their vehicles! As for the "depot" adjacent to the carriageway, I was told that it seemed to be stables and the buildings were not controlled by the Highways Agency. Further independent investigations confirmed that the "depot" is in fact various farm buildings known locally as "The Paddocks". So that's cleared that up then!

It seems strange for the Police to have an expensive specially constructed "emergency turnaround point" which is locked and has to be opened by officers carrying keys with them! It also seems funny that the slip roads are EXIT ONLY - there are no matching entry slip roads. Only when you take a step back from the junction and look at the "big picture", do you start to get interested in the other possibilities.

Studying the special 1:2500 data more closely and paying particular attention to the hard shoulder layout at each slip road location (indicated below), you realise that it is just about possible that each slip road (one on the eastbound carriageway and one on the westbound) can be used by Police vehicles to exit AND enter the M4. The exit mode is by using the slip roads in the normal manner by just filtering off the main carriageway to the left and dropping down onto Fosse Way. The entry mode is by using the slip roads from Fosse Way and then joining the main M4 carriageway by "doubling back" carefully.

Just a few miles north of the Fosse Gate "secret" junction, along the route of the Fosse Way, you will find Prince Charles's residence Highgrove House at Doughton near Tetbury, just over the border in Gloucestershire. A similar distance to the south, you'll spot that military airfield at Colerne and the various MoD bases in Corsham! Could the junction be also used by MI5 and Royal Protection Officers, escorting the heir to the throne and other VIPs? Whilst the official response from the Highways Agency through my FOIA application is obviously careful not to confirm this, it doesn't completely rule it out either! A thought I'll just have to leave with you ...

For a very subtle example, consider the M4 again but further east near Swindon. Take a close look at the hard shoulder in both directions near the village of Ballard's Ash, where the B4042 Malmesbury to Wootton Bassett road goes underneath. There are "Police Only" signs again. In the eastbound direction a steep slip road goes backwards down to the B4042 below. In the westbound direction, if you blink you will miss it. An area of grass banking leads to a locked gate, a farm track and eventually the B4042. Interestingly, RAF Lyneham is not far away and this "secret" junction could come in useful during heavy traffic to and from the airbase.

Yet more "secret" motorway junctions and slip roads!

Another amazingly similar junction to the one at Fosse Gate can be spotted, this time on the M6 motorway in Staffordshire, halfway between junctions 14 and 15 and just north of Stafford services. Take a look at the aerial photo of the M6 at Whitemoor Farm, Yarnfield .

The slip roads in this case are clearly visible from the air and this time, they are fully marked on OS maps at all scales. The layout differs from the "secret" junction at Fosse Gate in that the slip roads join the M6 at right angles and come from a minor road crossing over the top of the motorway. The aerial photo perfectly illustrates that each single slip road per carriageway allows authorised vehicles to both exit and enter the motorway.

Police vehicles have been observed using the slip roads regularly and this stretch of the M6 is often blocked by slow moving or standing traffic. It seems reasonable to assume that at times of heavy congestion, the junction is used by police and other emergency vehicles such as ambulances and fire appliances.

The intriguing "Training Centre" marked on the map alongside the junction is merely a large conference facility. Part of the site has been used by British Telecom (formerly GPO, the General Post Office) as its Central Training School for Engineers since 1946. Before that, during WWII, the facility's accommodation units had been used as military transit camps for USAF personnel.

However, take a look just a little further west and you'll spot the massive Swynnerton Army Training Area (a former WWII Royal Ordnance munitions factory) at Cold Meece near Stone, Staffordshire.

Take a look a little further south where the M6 passes around the west side of Stafford through the town of Doxey . You'll spot yet another non-public junction that is not officially numbered. This one seems to be a "Works Depot" but with a "Police Station" marked at the south west corner. The site was originally planned as a motorway service station that never materialised. Note the tarmacked bays on the west side of the M6 carriageway that may be used to hold emergency (or military?) vehicles. It actually turns out to be Staffordshire County Council's Motorway Maintenance Unit!

At the northern end of the M6, just before you head into the Lake District, you can discover an emergency turnaround junction just north of Carnforth in Lancashire. It's at Saltermire Bridge , between J35 and J36 and near Burton-in-Kendal services, which is northbound only. The police secret junction utilises two slip roads connected into Cinderbarrow Lane running over the motorway via the bridge.

Also on the M6 north of Preston, at Catterall near Garstang, you can find an emergency vehicle turnaround using a slip road on the northbound carriageway near Stubbins Bridge over the Lancaster Canal and another slip road southbound near Claughton-on-Brock. The two slip roads allow a turnaround using Stubbins Lane to the north, which runs underneath the motorway. On the north side of Stubbins Lane is a Lancashire County Council highways depot , whose gritter lorries will also use the "secret" junction.

If you scrutinise the M25 orbital motorway around London near Denham Aerodrome in Buckinghamshire, you'll spot yet another "secret" junction . It utilises part of an existing track leading to Coldharbour Farm to the west and also a new access road hidden within Nockhill Wood to the east. This junction would seem to be designed to allow emergency vehicles to quickly turnaround and head in the opposite direction by dropping down onto Slade Oak Lane, the minor road running underneath the M25 just to the north.

If you regularly turn off the M25 to head north west on the M40, look out for another secret junction at Fulmer near Gerrards Cross in Buckinghamshire - again for use by emergency vehicles. If you follow Fulmer Lane from here a little north east towards the A40, you'll spot another secret turnaround junction on the M25 at Tatling End . Stay on the M25 but look near Iver Heath at Palmer's Moor Farm . Yes, another handy secret junction for the police!

Take a look at Brasted near Sundridge in Kent. The route of the M25 carriageway just north of the village follows the path of an old train line. At what was Brasted's station, you'll find another "secret" turnaround junction , which uses two slip roads – one for each carriageway – constructed west and east of the location, connected via the old Station Road which now goes underneath the motorway. This junction would also have made a very handy short-cut to and from Chevening House , which in the past has traditionally been the official residence of the Secretary of State for the Foreign Office!

Further east on the M25 towards Sevenoaks, there's an emergency access point on London Road in Dunton Green, near to where the Pilgrims Way crosses the M25 motorway. Incidentally, just to the north west over the other side of the M25, you'll find a top secret Government research laboratory hidden in the woods near Knockholt.

Even further east but on the M26, yet another secret junction can be found at Otford . It allows emergency access to and from the motorway by utilising the original Sevenoaks to Otford road that existed before the new A225 dual carriageway was built over the top of the M26.

Still in Pilgrims Way country, but further towards the Kent coast, consider the A2 London to Dover trunk route near Canterbury. Pay particular attention to a curious private slip road onto the eastbound carriageway near the village of Nackington. Perhaps all is explained when you realise that the large compound of buildings just north of the A2 at the junction of Nackington Road and Merton Lane, where that slip road leads directly in to, is a police vehicle storage and maintenance depot . The site has a very interesting history – it was once the Nackington outstation (or "detachment") for the main Cranbrook regional depot of the Home Office's Directorate of Telecommunications (DTELS), where police and other emergency vehicles would be fitted with specialist, sometimes covert, radio equipment.

A couple of secret slip roads can be spotted right in the middle of all the public ones at Junction 10 of the M4 near Wokingham between Reading and Bracknell, Berkshire. The two extra slip roads, for emergency turnaround use by police vehicles only, can be found north west and south east of J10 but are not marked on even 1:10000 maps!

Take a look at the M5 between public junctions 11a and 12 at Sneedham's Green , just south of Gloucester. Right next to Snow Capel (or Chapel) Farm, you can spot another classic "secret" turnaround junction which utilises a minor road passing over the motorway. This junction is visible on all current mapping but at 1:10000 scale from MAGIC, it is even helpfully labelled "Emergency Access"!

Note how it is very close to the Highgrove home of Prince Charles in Tetbury. It would make a very useful escape route for His Royal Highness and accompanying MI5 / Royal Protection Officers to avoid those troublesome traffic snarl-ups! Then again, it is also close to the numerous military storage depots, now abandoned and redeveloped, which once formed RAF Quedgeley .

Close to GCHQ's Doughnut spy HQ in Cheltenham, take a look at Junction 11 of the M5 where the A40 intersects. There are a couple of extra slip roads not for use by the public, on the north east corner of the junction. One leads into a highways maintenance depot, but the other provides rapid deployment for Gloucestershire Police's Operations Centre – including serious crime armed response units – next door on Bamfurlong Lane which leads out to Staverton Airport.

Still in Gloucestershire but some distance from the M5, you wouldn't believe me if I told you that there was a whole secret motorway, not just a secret junction! But it is little more than half a mile long, has no junctions at all and is hidden inside an old RAF base. Confused even more?

The M96 secret motorway isn't up in Scotland, as the numbering would suggest, but in the former WWII bomber base at RAF Moreton-in-Marsh, in the heart of the beautiful Cotswolds.

The airfield was taken over in the 1960s by the Fire Service Training College. The old runways have been covered by all kinds of fire simulation training scenarios including high-rise buildings, trains & tracks with station platforms, aircraft and even reconstructions of an offshore oil rig and a ship in dock.

One of the runways has been laid out as a replica of a motorway dual carriageway complete with hard shoulders, central reservation and even an overhead gantry with the fake "M96" sign in place.

• www.fireservicecollege.ac.uk

Back on the M5 but in Worcestershire, another "secret" emergency turnaround junction for the police can be found at Gallops Bridge near High Green. Interestingly, this is very close to the old disused QinetiQ SIGINT enclave at Defford, which is now used by West Mercia Police as a vehicle maintenance depot!

Another emergency turnaround junction can be spotted on the M3 in Hampshire at Micheldever , between Basingstoke and Winchester. It uses the minor road passing over the motorway between the A33 and the village of East Stratton.

Two turnaround junctions are situated on the M11 in Essex around Saffron Walden. One is at Newport and the other is at Great Chesterford just south of the public junction 9 with the A11. It uses an old track which actually passes underneath the motorway carriageway in a tunnel. The tunnel theme is used elsewhere too – read on!

Still on the M11 in Essex but much closer to London, take a look at a couple of secret slip roads near Theydon Bois (pictured above). There's one on the southbound carriageway and another on the northbound carriageway, which also obviously serves a curious depot. Both slip roads allow authorised vehicles to enter and exit, but this non-public junction is only a few hundred yards south of the major M25/M11 interchange.

The reason is quite obvious when you take a much closer look at the contents of the adjacent depot on the Bird's Eye aerial photo. The Theydon Bois secret junction is for the use of Highways Agency maintenance vehicles and gritter lorries. They are able to use Coopersale Lane which passes over the top of the M11. Of course, it is very handy for emergency vehicles to perform turnarounds too.

Look out for another turnaround nearby on the M25 at Theydon Mount between junctions 27 and 28.

A quite famous secret junction further into London at Chigwell was originally planned as a motorway services area which never actually got built. On the north west side of the junction there is a large police control room, so don't be tempted to use those slip roads which are so invitingly free of traffic!

An impressive cluster of no less than four secret motorway junctions can be found close together around the Langham Interchange at M62 J35 / M18 J7 on Humberside. Check them all out at Pollington , West Cowick and Rawcliffe on the M62 and at Greenland Bridge on the M18.

RAF Fylingdales wasn't shown on 1:50000 scale OS maps until a major revision was launched in July 2006. Until then, you had to go to the more detailed 1:25000 scale data to finally reveal RAF Fylingdales and it is actually on top of Snod Hill rather than Fylingdales Moor, but the name "RAF Snod Hill" just wouldn't have worked somehow!

It is curious that, since the end of the Cold War, Menwith's "golf ball" radomes have actually multiplied like rabbits. The old "golf balls" at Fylingdales were dismantled many years ago, to be replaced by state of the art Phased Array Radar (PAR) units. The three-sided concrete plinth (thereby giving 360º coverage), upon which these PAR units are mounted, can clearly be seen on Multimap's aerial photo.

From 2010, Menwith Hill's Echelon signals interception system is being massively expanded as part of the Global War on Terror (GWOT). By comparing aerial photography, it can be revealed that the base's West Gate security entrance has been radically redesigned to incorporate a new Visitor Control Centre and Vehicle Inspection Buildings. Furthermore, plans submitted to neighbouring Harrogate Council in early 2009 show that the main hardened and semi-sunken mission facility – Building 1045 (codenamed Steeplebush II) – is being significantly extended south onto spare land with a new Sensitive Compartmented Information Facility (SCIF) project valued at $31 million, plus $10 million for improved power infrastructure to support it.

Nowadays, Menwith Hill is actually labelled on the latest OS maps as "Menwith Hill Camp", making it sound like an innocuous barracks full of harmless squaddies. In reality, Menwith Hill is used to intercept communications in conjunction with GCHQ.

Because it was originally illegal for GCHQ to spy on its own UK citizens, this problem was easily circumvented by having the US owned Menwith Hill do the dirty work for them. Because of this US control, British MPs trying to ask questions in Parliament about the base just came up against a brick wall. With the introduction of recent far-reaching Acts of Parliament, handing more powers to both GCHQ and MI5, virtually anything goes!

On the subject of squaddies, just east of the Menwith camp, on the road into Harrogate, there's the Army Foundation College . It is the centre for junior soldier induction training, split between the sites of the old Uniacke Barracks (south of the road) and Hildebrand Barracks (north) on Penny Pot Lane.

While in Yorkshire, take a look at the centre of York itself. On Fulford Road you'll find Imphal Barracks. More squaddies, you think. But look beyond the razor wire fencing and to the rear of the site, you can find the Defence Vetting Agency where extensive background checks on applicants to MoD related jobs are performed and detailed records are kept.

Interestingly, right next door to Menwith Hill, the DCSA have another base which they refer to as HMS Forest Moor . It is responsible for routing communications for the Royal Navy. The OS 1:50000 series map shows HMS Forest Moor as a tell-tale geometrically shaped building, but is not labelled. Up to the end of 2004, if you went to the 1:25000 OS map, the building disappeared! If you tried the Government's MAGIC interactive mapping website and checked the 1:10000 scale map , HMS Forest Moor reappeared and the empty "farmer's fields" immediately to the south suddenly sprouted aforest of aerial masts, fully labelled. Now that's what I call MAGIC!

Indeed, as if by magic, in November 2004 the online version of the 1:25000 scale map from the OS Get-a-map website suddenly started showing HMS Forest Moor in all its glory with a cluster of aerial mast symbols, as detailed on the 1:10000 map!

The old Royal Navy centre next to the road has now been abandoned and is currently being considered by property development companies. One such company has applied to Harrogate Council for planning permission to convert the administration and accommodation blocks for HMS Forest Moor into a medium security mental health hospital.

Meanwhile, the newly updated 1:25000 map also finally revealed what seems to be the DCSA's control building for the aerial farm to the south of the road, which is unaffected by any future plans for the main HMS Forest Moor site.

It has been widely suggested that both the DCSA and GCHQ have operatives working on covert signals interception projects within Chetwynd Barracks at Chilwell near Beeston, Nottingham. At first sight though, this base would apparently just be part of the Defence Storage and Distribution Agency (DSDA) network. Chetwynd was also used as a major training and mobilisation centre for the war in Iraq.

Other key DCSA communications facilities can be found at Inskip , near Preston in Lancashire, at Anthorn on the Solway Firth coast in Cumbria and at Crimond on Scotland's Aberdeenshire coast between Fraserburgh and Peterhead, next to the St. Fergus North Sea Gas Terminal . One of the main communications masts at DCSA Crimond is shown below, in new aerial photography from Getmapping released in Summer 2005.

Predictably, both of the DCSA Inskip and DCSA Crimond sites are labelled "Disused Airfields" on 1:25000 scale OS maps! Anthorn is not labelled at all, although it is a former Royal Naval Air Station (RNAS) and now forms part of the network of communications sites tracking the UK's Trident submarine fleet.

In early 2006 it was announced that from April 2007, Anthorn was also going to take over the transmission of the UK's accurate time signal using atomic clocks. Since 1927, the signal had been transmitted from the Rugby site in Warwickshire, which in more recent decades had also been part of the MoD radio network tracking submarines carrying the nuclear deterrent.

If the US Government wants to perform commercial espionage in Europe, then it's easy - just use Menwith Hill. The scandal surrounding the Airbus contract a few years ago, confirmed Menwith Hill's role in this murky world. The communications involving the bidding process by the various companies vying for the contract were intercepted by the NSA at Menwith Hill. The details were passed directly to the US Government, who then made sure their own US companies were furnished with this "insider knowledge". Thus, the US companies mysteriously landed the contract!

This scandal and the Echelon system of communications eavesdropping centred around Menwith Hill have been extensively documented by Duncan Campbell - an author, investigative journalist and TV producer and one of the world's most authoritative independent experts on SIGINT (signals intelligence).

In a court case involving women peace campaigners a few years ago, a blundering British Telecom official accidentally revealed in open court that those nice BT engineers had connected fibre optic cables into Menwith Hill from their own communications site at nearby Hunters Stones . These cables are said to provide the Menwith Hill base with over 100,000 UK telephone lines.

Menwith Hill does perform important work in counter-terrorism. The telephone calls between the terrorists plotting the "9/11" (September 11th 2001) hijackings were picked up by operatives at Menwith Hill. Tragically, by the time the masses of data had been assembled, passed to GCHQ for analysis and decoded by "spooks" at MI5, the World Trade Centre's Twin Towers and all their occupants had been turned to dust.

After the attempted repeat wave of London bombings of 21st July 2005, following the original atrocities of 7th July, one of the alleged terrorists was tracked all the way to Rome by GCHQ/MI5 operatives working closely with Menwith Hill, by plotting his mobile phone intercepts.

In an amazing revelation, 19th century maps of the area show that the base is built directly above large disused quarry workings. So it seems that many of Menwith Hill's activities are buried underground in many levels of secret blast-proof bunkers and tunnel networks!

British Telecom seems very keen to keep its chums in MI5 and GCHQ happy. BT's massive research laboratory at Martlesham Heath , near Ipswich in Suffolk, routinely takes apart all new communications equipment that is produced so that "spooks" know precisely how to hack into them! At BT's "switching centre" located in the Shropshire town of Oswestry , GCHQ is handed phone tapping opportunities on a plate.