PROBE: The Zero Imperative

Caroline John

— Dr. Elizabeth Shaw

Jon Pertwee

— Dr. Jeremiah O'Kane

Sylvester McCoy

— Dr. Colin Dove

Colin Baker

— Peter Russell

Mark Gatiss

— Dr. William Bruffin

Louise Jameson

— Patricia Haggard

Sophie Aldred

— Public Relations Officer

Linda Lusardi

— Louise Bayliss

David Terence

— Daniel O'Kane / Eustace O'Kane

Nicola Fulljames

— Dr. Beatrice Hearst

Patricia Merrick

— Dr. Julie Gilchrist

Jonathan Rigby

— Cummings

Alexander Kirk

— Orderly

Daniel Mills

— Ghostly Child Voice

Peter Davison

— Patient One