John Ronane

as Professor McLaughlin

as Halo

as Mr. Mayer (1 episode)

as Councillor Steven Moffat (1 episode)

as Ben Turnbull (1 episode)

as Self (1 episode)

as Arthur Field (1 episode)

as Bob Cooper

as Policeman (1 episode)

as DS David Singer (10 episodes), as DI David Singer (10 episodes)

as Dowson (1 episode)

as Bill (1 episode)

as Dr. Rawley

as Red Redgrave (1 episode)

as Rupert Hathaway (archive footage)

as Roland Smallbody

as Harold Barnes (3 episodes), as Robert Randell (3 episodes)

as Paul Medbury

as Rupert Hathaway (1 episode)

as Quilter

as Thomas Seymour (1 episode)

as Thomas Seymour (2 episodes)