Their main purpose was to act as collection and interrogation centres for newly captured aircrew, before they were transferred in batches to the permanent camps.

A satellite camp at Wetzlar was set up later in the war to help cope with the large numbers of aircrew captured as the bombing campaign intensified against Germany.

The camp was built on the site of an old government poultry farm, approximately 300 yards north of the main Frankfurt to Bad Homburg road.

The main building, known as the stonehouse, had been used as a prison for a small number of airmen captured in the early months of the war, before it became a transit camp.

Buckley was a pilot in the Fleet Air Arm and as such the Germans had placed him, with all other FAA aircrew, under the responsibility of the Luftwaffe.

The third tunnel ran west from the western barrack block under a sentry tower on the south-western corner of the camp.

The escapers, including Day, Buckley, Johnnie Dodge and future Carry On film star Peter Butterworth, were all recaptured within a week.

It is reputed that the German Camp Commandant Major Rumpel gave the escapers a case of champagne with the words "Better luck next time, even if I'm not supposed to say so".