Hayley Mills ... Susan Harper
Hywel Bennett ... Martin Durnley
Billie Whitelaw ... Joan Harper
Phyllis Calvert ... Enid Durnley
Frank Finlay ... Henry Durnley
Barry Foster ... Gerry Henderson
Salmaan Peerzada ... Shashie Kadir (as Salmaan Peer)
Christian Roberts ... Philip Harvey
Gretchen Franklin ... 'Clarkie'
Thorley Walters ... Sir John Forrester
Timothy Bateson ... Mr. Groom
Clifford Cox ... Insp. Goddard
Richard Davies ... 'Taffy' Evans
Basil Dignam ... Doctor
Mollie Maureen ... Lady Patient
Russell Napier ... Prof. Fuller
Robin Parkinson ... Shop Manager
Brian Peck ... Det. Sgt. Rogers
Timothy West ... Supt. Dakin