Dr Tuck believes George was begun in about September 1944, before the arrival of freezing conditions in winter that would have made digging impossible.
Stalag Luft III held more than 10,000 RAF and US air force prisoners, and it is estimated about a third would have assisted in preparations for the Tom, Dick and Harry breakout.
Far fewer would have worked on, or even known about George, Dr Tuck believes.
“This tunnel was uber-secret, this was another level of secrecy,” he says, which partly explains why so little is known about the tunnel.
Story: BBC News | Photo: Wikimedia Commons