Thank you very much Paul and Steve. Having read 'apple pie' I seem to remember 'Christmas pie' came into it somewhere. The Scouse inmate was in for car theft (among many other things!), so perhaps he and his mates changed the words to 'stolen car'. The tune he sang it to was indeed very similar to My Old Man's A Dustman. He really used to crease me up with this song and his broad accent. He also I remember had a song that started "Are you right there Michael are you right?" which he sang in an Irish accent.