The Zero Imperative

Caroline John

as Dr. Elizabeth Shaw

Jon Pertwee

as Dr. Jeremiah O'Kane

Sylvester McCoy

as Dr. Colin Dove

Colin Baker

as Peter Russell

Mark Gatiss

as Dr. William Bruffin

Louise Jameson

as Patricia Haggard

Sophie Aldred

as Public Relations Officer

Linda Lusardi

as Louise Bayliss

David Terence

as Daniel O'Kane / Eustace O'Kane

Nicola Fulljames

as Dr. Beatrice Hearst

Patricia Merrick

as Dr. Julie Gilchrist

Jonathan Rigby

as Cummings

Alexander Kirk

as Orderly

Daniel Mills

as Ghostly Child Voice

Peter Davison

as Patient One