John Mills as Supt. Mike Halloran

Charles Coburn as Dr. John Fenner

Barbara Bates as Elizabeth Fenner

Derek Farr as Mark Roper

Alec McCowen as Peter Crowley (as Alec Mc Cowen)

Fay Compton as Mrs. Crowley

Geoffrey Keen as Charles Dixon

Margaretta Scott as Helen Dixon

Meredith Edwards as Police Sgt. Rogers

Harry Locke as Police Sgt. Beale

Raymond Huntley as Dr. Reese

Harry Fowler as Leslie (Bandleader)

Maureen Connell as Mary Roper

Magda Miller as Molly Stevens

Newton Blick as Asst. Commissioner Beckett

Oscar Quitak as David

Totti Truman Taylor as Mrs. Gerrard

Grace Arnold as Club Committee Woman

Elizabeth Seal as 'Fiona' / Fiona Dixon