She started her acting career in the TV film The Rainbow, based on the novel by D.H. Lawrence. She played Harper in the Royal National Theatre's production of Tony Kushner's Angels in America in November 1993. Clare was nominated for 1997 Laurence Olivier Theatre Award for Best Actress in a Supporting Role of 1996 for her performance in Who's Afraid of Virginia Woolf?. In 1991, she played Iris Bentley, sister to Derek Bentley, played by Christopher Eccleston, in the film "Let Him Have It".