This handsome wartime Royal Air Force man I found in a flea market was my introduction to the Polyfoto process, which was quite popular in 1930s and 40s Britain. Polyfotos were offered in department stores. The subject would sit in front of a camera that would take 48 photographs in rapid sequence. These were presented to the customer in a single sheet of numbered passport size photos. See this website for a wonderful animated sequence that one film maker has made out of polyfotos of his parents. The customer could order enlarged versions of their favourite shot. More often they cut the sheet into pieces, like this one. I have created a Flickr group for Polyfotos if you'd like to see more.
This chap attracted over 1000 views from the RAF Facebook page and several people currently in the service expressed a desire to find out who he was. No luck yet though. It looks like he was an NCO posing in a borrowed officer's cap for a laugh. I have found two other (non-Polyfoto) shots of him with his wife. Possibly he didn't survive WW2.