Here’s a thread which will give valuable info:
There were three ways to get out of a Stalag or Oflag: over the wire (most risky); through the wire; or under the wire.
“Over the wire” was generally attempted only in extreme weather conditions, or during an air-raid blackout (or, as in the “Eichstatt job,” by fusing the lights deliberately). One brilliant escaper went over the wire in broad daylight: carrying a ladder, dressed in overalls as a German maintainence man, he busily “checked” the electified warning wire on the fence with a fake volt meter, and at a predetermined point, deliberately dropped the meter on the outside of the wire. The bored guards in the boxes watched placidly as the “German” repairmain used his ladder to climb up, then over the outside of the wire to retrieve his meter. The POW then made a great show of the meter being broken, and walked off into the German compound “to get a new one.”
“Through the wire” could be either cutting through (again, very risky, as you would perforce be inside the “zone of death” along the inside of the wire and could be shot on sight). “Through” also included the incredible act of dressing up as German military guards, german civilian workers, Swiss Red Cross men, etc. Generally you needed excellent German language skills from at least one of your party, as well as detailed knowledge of camp security procedures (passes, gate routine, layout of the Kommandantur, etc. One of the ballsiest Colditz escapes involved a red-haired British officer (Mike Sinclair) impersonating not just a German NCO, but a specific German NCO, nicknamed “Franz Joseph,” who had luxuriant whiskers reminicent of the late Austro-Hungarian emperor. All went well until the real “Franz-Joseph” turned up while the fake was trying to talk his way out.
“Under the wire” meant tunnelling, either a long-term job from a hut, requiring trapdoors, wooden revetting, sometimes an air pump, etc., or a “mole” job, which was simply digging under the wire afer dark, filling behind you as you went–a “blitz” job.
As for “material similar to that of the German coat,” if you were a British Air Force type, your greatcoat could be lightened (temporarily) by the use of powdered chalk or talc carefully brushed in. This would approximate the Luftwaffe blue. (Remember that most Allied aircrew POWs were guarded by the Luftwaffe, and most Allied Army types were in Whermacht-run camps). The distinctive “feldgrau” of the German Army was quite close to the Dutch army uniform: if, as in Colditz, you had some Dutch army POWs, you might strike a deal.
One of the best escapes that I have read about was quite early in the war (Summer 1941), where a British Royal Navy officer, after cutting his way out of a camp, travelled openly on the German railways in his Royal Navy uniform. His false papers named him as an officer in the Romanian Navy–since there are no English words on the RN uniform, and no-one was familiar with what a Romanian Navy officer’s uniform looked like, he was pretty safe (although IIRC, he was arrested trying to cross the Swiss border). The best part was that his false papers were made out to an “Ivan Bagherov,” or “I. Bagherov,” pronounced “I buggeroff:” a Britishism for “I’m outta here!”