RAF Medmenham - Second World War

Second World War

In April 1941 an RAF photographic interpretation unit (PIU) moved to Danesfield House, Medmenham, as its previous location at Wembley was short of space, and was renamed the Central Interpretation Unit (CIU). Later that year the Bomber Command Damage Assessment Section was absorbed, and amalgamation was completed when the Night Photographic Interpretation Section of No 3 Photographic Reconnaissance Unit, RAF Oakington, was integrated with CIU in February 1942.

During 1942 and 1943 the CIU gradually expanded and was involved in the planning stages of practically every operation of the war, and in every aspect of intelligence. In 1945 daily intake of material averaged 25,000 negatives and 60,000 prints. By VE-day the print library, which documented and stored worldwide cover, held 5,000,000 prints from which 40,000 reports had been produced.

American personnel had for some time formed an increasing part of the CIU and on 1 May 1944 this was finally recognised by changing the title of the unit to the Allied Central Interpretation Unit (ACIU). There were then over 1,700 personnel on the unit's strength. The title of the unit reverted to Central Interpretation Unit when the Americans returned home in August 1945.

Early in 1945 a number of photographic interpreters (PIs) were sent to join the British Bombing Research Mission in Paris to explore the degree of damage and production interruption caused by Allied bombing in the Resistance areas of the Central Massif and in the ports. They were also tasked with checking PI reports which would eventually be related to assessment reports of attacks on German industry. Several PIs were also seconded to The Pentagon in Washington, D.C. to join a detachment of RAF and British Army Officers.

The Spitfire, without any guns but with a cruising speed of 360 mph at 30,000 feet, was used for photo-reconnaissance missions. The aircraft was fitted with five cameras which were heated to ensure good results (while the cockpit was not). Another key aircraft was the Mosquito which had a cruising speed of 255mph, maximum of 362mph and a maximum altitude of 35,000ft. Thirty-six million prints were made during the war, of which some 10 million, many in 3-D, still survive and are today kept in Edinburgh. A large number of Photographic Interpreters were recruited from the Hollywood Film Studios including Xavier Atencio. Dirk Bogarde was employed in the Army reconnaissance section as a visual inspector. Two renowned archaeologists also worked there as interpreters: Dorothy Garrod, the first woman to hold an Oxbridge Chair, and Glyn Daniel, who went on to gain popular acclaim as the host of the television game show Animal, Vegetable or Mineral? Up to 150 women were also employed as PIs.

Of particular significance in the success of the work of Medmenham was the use of stereoscopic images, using a between plate overlap of exactly 60%. Having overcome the initial scepticism of Lord Cherwell to the possibility of the new rocket technology, major operations made possible by the work at Medmanham included, on 17 and 18 August 1943, an offensive against the V-2 rocket development plant at Peenemünde. Later offensives were also made against potential launch sites at Wizernes and 96 other launch sites in Northern France. It is claimed that Medmanham's greatest operational success was "Operation Crossbow" which, from 23 December 1943, destroyed the V-1 infrastructure in Northern France.