Scotttish film from about 20 years ago with accents so thick they sound like another language?

About 10 years ago I caught the end of a film obviously set in Scotland - probably late 60's early 70's time period. There was a group of young teens, girls and boys, hanging around barren working class streets. Clean but impoversished. They were bantering back and forth in an accent or dialect only barely recognisable as (originally at least) English. Any suggestions?