Big X
Buckley, with all other POWs from Barth, was transferred to Stalag Luft III in April 1942. The escape organisation remained unchanged with Buckley at its head. To improve security and provide anonymity from the Germans, Buckley became known as 'Big X' – a term later made famous by its use by Roger Bushell and the character based on him, played by Richard Attenborough in the film, "The Great Escape".