“In a tiny compound 600 R.A.F. and Dominion airmen worked for a year under the strictest secrecy on the great tunnels Tom, Dick, and Harry. These were hundreds of feet long, with underground railways, workshops, air pumping stations and deep enough to avoid German sound detectors. Under the very noses of alert German guards the prisoners organized factories for making German uniforms, compasses, maps and documents and even a studio for fake passport photographs.”