Peter Cushing as Detective Inspector Quennell

Robert Flemyng as Dr. Carl Mallinger

Wanda Ventham as Clare Mallinger

Glynn Edwards as Sgt. Allan

Kevin Stoney as Granger the Butler

Vanessa Howard as Meg Quennell

David Griffin as William Warrender

Roy Hudd as Morgue Attendant

William Wilde as Frederick Britewell

Simon Cain as Clem Withers

Russell Napier as Landlord

John Paul as Mr. Warrender

Leslie Anderson as Coachman Joe Trager

David Lyell as Student with Toy Spider

Drew Russell as Constable Smith

Robert Cawdron as Chief Constable

Kenneth Colley as James

Roy Evans as 2nd Porter