Former Flight Lieutenant Jack Lyon, 96, was 25 when he entered Stalag Luft III's north compound. He became involved in the escape after being moved from the east to the north compound but, he says, escape information was strictly on a 'need to know' basis and he had no idea how truly audacious the plan was.
Some 600 men were involved in executing the Great Escape plan, from tunnel engineers, master forgers and carpenters.
Jack says: "Early in 1944 it became obvious that there was a good deal of clandestine activity. When you have regular collection of bed boards, it pretty well tells you that tunnelling is going on – as well as the continued procession of prisoners in long coats around the camp perimeter!
"Someone approached me and asked if I wanted to take on some work or other and I agreed to do surveillance, which they called stooging – basically they wanted me to keep track of the Germans day and night. The most difficult thing was not to let your attention falter and particularly not to nod off at night. It’s a long and boring thing, looking at nothing!
"I knew there was a tunnel, but, remember, I didn't know where it was or anything about its details. There was no need for me to know.
"I found out the day before the escape that it was actually happening, they'd drawn the numbers and I was part of the 200 drawn to go through the tunnel. We knew the escape day was imminent but it wasn't until sometime after midday on 24 March, after Len Hall who was the meteorological officer gave Roger Bushell a reasonably good weather report, that I knew it was definite.
"Len gave as accurate a report as you could get and Roger decided that was it – the plan would go ahead – he had to decide very quickly because all the papers had been dated..."