Cast Credits Midsomer Murders (1998) Guest starring as Doctor Frost Episode 14x02: Dark Secrets (Mar 30, 2011) Blake's 7 (1978) Guest starring as Practor Episode 4x03: Traitor (Oct 12, 1981) Play for Today (1970) Guest starring as Craig Episode 2x01: Traitor (Oct 14, 1971) Special Branch (1969) Guest starring as Eastry Episode 4x03: Jailbait (Feb 28, 1974)