Caroline's part in The Bill was the first of a series of three long-term roles in which she played police officers - The Vice had her demoted to PC, whilst in Murder in Suburbia she was a Detective Inspector. She is currently starring in Doc Martin, where she enjoys playing primary school headmistress Louisa Glasson. “Part of the fun of playing this role for me is that Louisa is constantly making the same mistake. Every encounter she has with Martin she thinks she can improve him. It is absolutely ridiculous, she can’t," she saysMore Caroline Catz