Plainclothes Policeman

The film

For want of a nail a shoe was lost, for want of a shoe... a young man's life is almost lost, which is exactly what this film is all about: a man barely twenty who wants desperately to pull out of London's drug world by taking a job as a waiter in a 'normal' restaurant. But to do this he must come up with a "sensible" pair of shoes, an item that his homeless meanderings hasn't provided him.

Synopsis from TMDB.