Intelligence Work at Secret Sites Revealed for First Time

From five unlikely locations across the UK, including a farm-house outside London and a manor on the White Cliffs of Dover, GCHQ carried out top secret operations, including:

  • Identifying and deciphering secret communications between Adolf Hitler and his field marshals;
  • Intercepting a fax for the first time in British intelligence history to help prevent Japanese fighter pilots getting the better of our America allies; and
  • Mounting our Cold War efforts against the Soviet Union, by pioneering the interception of communications from its army, navy and air force.

We have revealed the work done at these little-known sites to provide an insight into signals intelligence over the course of our 100-year history.
These locations, dotted around the UK, have long since closed down – to be replaced by the organization’s better known sites in Cheltenham, Bude and Scarborough, and the National Cyber Security’s offices in Victoria, London.

As Director GCHQ Jeremy Fleming has said, the past century has seen GCHQ “save countless lives, given Britain an edge, and solve and harness some of the world’s most complex technological challenges”.

From a quiet farm house in Kent to a discreet office block in Mayfair, our 100-year history is full of ordinary people working together to solve extraordinary problems. That work continues today at and around secret locations across the UK.

Ivy Farm: Intercepting Hitler’s orders

Operational in the Second World War, Ivy Farm, Knockholt Kent was the home to the Headquarters for the Foreign Office Research and Development Establishment, which sits within GCHQ in Cheltenham today. Staff numbered between 60-100.

Operations: Rather than monitoring voice or Morse Code, for the first time in UK Intelligence history staff at Ivy Farm investigated what is known as “noise” – sound which does not carry human communications. Some of the UK’s brightest technologists were brought in to work at this site, including from the Post Office (where Tommy Flowers, who made the world’s first computer started work on Colossus). This noise carried the secret to Adolf Hitler’s most secure communications with his field marshals across Europe. It used encrypted teleprinter technology, which was many more times secure than Enigma.

Interesting Fact: Staff successfully intercepted and isolated this “noise” which was passed onto Bletchley to decipher, and ultimately lead to the creation of the world’s first computer Colossus. The site was also responsible for the first-ever UK interception of fax. A Japanese press attaché in Berlin had sent a fax, featuring details of US bomber squadrons and formations, to a Tokyo-based press agency intended for the Japanese military so they could better attack the US air force. This information was passed to US allies so they could adapt their tactics accordingly.


Abbots Cliff House: Women protecting the White Cliffs of Dover

Operational between 1940 and 1945, Abbots Cliff House at Capel le Ferne had between 50- 60 people working there.

Operations: This base collected Very High Frequency (VHF) communications from Germany directing aircraft or fast moving E-boats in the English Channel. VHF has a very short range which meant that German linguists, mainly young women, were sent to the front line to live log the communications.

Interesting Fact: This type of interception had never been done before for voice communications and the tactical nature of this job meant that every day the information collected by these young women was helping to protect British pilots and sailors. German forces would try to capture British pilots downed over the Channel and information from Abbots Cliff House would have helped to save some British pilots during the war.

Today: Abbots Cliff House is still there today, with views across to France.

Chesterfield Street: The start of Cold War operations

Operational between 1944-1953 the site in Mayfair, London, started with around 10 people before hosting up to 60 at capacity.

Operations: This office block was the start of what became GCHQ in the Cold War. All soviet targets were worked on from this office and the first interception of army, navy and air force was achieved here. The office stayed open until 1953 when the recently avowed Palmer Street office near St James’ Park was opened to consolidate all of our London offices

Interesting Fact: Bill Bonsall joined as one of the 10 people in 1944, mainly working on German Airforce intercept. He later went onto become Director GCHQ in 1973.

Today: It is now the site of the High Commission of The Bahamas which was first established in the 1970s.

Marston Montgomery: The first woman commander

This site, in Marston Montgomery, Derbyshire, made up of a series of wooden huts in a remote location, was set up in 1941 and closed in 1947. Around 100 people were based here.

Operations: Set up as an outstation of RAF Cheadle, the Head Office for RAF Sigint, Marston Montgomery was the home of technical radio and operator fingerprinting. Staff would be listening to at least 25 different operators each, identifying individual radio signals – for example by the speed that people would tap out Morse code. Once enemy operators were identified this information could be used to piece together troop movements.

Interesting Fact: This was the first GCHQ base to have a woman commander, 2nd officer Pamela Pigeon.

Today: The site was dismantled after the war.

Croft Spa: Farming for enemy signals

Located just south of Darlington this site was operational between 1940- 75 and was home to up to 20 operators.

Operations: Croft Spa was a direction-finding station – which meant it worked in conjunction with other sites to pinpoint the location of enemy signals from ships in the North Sea.

Interesting fact: This tiny rural station, on the edge of a military facility, was the perfect place to locate a listening station due to the low noise floor. However, when agriculture became more mechanised, the staff frequently had to ask local farmers to stop their work (but not told why) so noise from the machinery did not interfere with the collection of important communications.

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