Robert plays Steve, a young man working on a building site. His troubled girlfriend, Susan, with misguided aspirations of becoming a singer, is played by Emer McCourt.
As is common with Ken Loach's work, the actors draw heavily upon their improvisation skills. According to Scotland on Sunday (26 May 1991), the film was made on a budget of £800,000 and filmed chronologically on a real building site over a period of five weeks. In the same article, Robert Carlyle recalls his audition for the role of Stevie: "At the first meeting, Ken Loach seemed to do most of the talking and I found myself on the way out after a couple of minutes. And then I turned and said, 'but you're looking for people who have worked on building sites - and I've done all that as a painter and decorator'. I explained the background and I was invited back to do some improvisations. He interviewed about 60 actors, and he just kept whittling away over a period of a month. It was pretty stressful; then it was down to two of us." Needless to say, Carlyle got the part. Riff Raff was screened at the Cannes Film Festival in 1991, where it received the international critics' award in the Directors' Fortnight.