Among her film appearances are roles in Stardust (1974), The Brute (1977), The Krays (1990), The Russia House (1990), White Hunter Black Heart (1990), The Saint (1997), Ghosts of Mars (2001) and Dead Space: Aftermath (2010) (voiceover). Cornwell has also worked extensively on television including appearances in Rock Follies, The Men's Room, The Governor, Shalom Salaam, Lovejoy, Love Hurts, Where the Heart Is, A Touch of Frost, Silent Witness, The Mentalist, Dressing for Breakfast, Capital City, The West Wing, Casualty, The Practice, New Tricks, Toast of London, and Midsomer Murders, among other television programmes in Britain and the United States.