Cmdr. Michael Haydon

Kieron Moore

Kim Hamilton

Lois Maxwell

Jimmy Wheeler

Bryan Forbes

Prof. Merrity

Donald Wolfit

Barbara Noble

Thea Gregory

Larry Noble

Jimmy Hanley

Lefty

Barry Keegan

Professor Blandford

Walter Hudd

Colonel Galloway

Alan Gifford

Captain Ross

Donald Gray

Ellen

Shirley Lawrence

Tony

Peter Neil

Reporter

Ryck Rydon

Reporter

Ronan O'Casey

Reporter

Robert O'Neil

Reporter

Robert O'Neill

Professor Bechstein

Carl Jaffe

General Barnett

Charles Richardson

Official (uncredited)

John Baker

Simmons the Technician (uncredited)

Trevor Reid

Technician (uncredited)

Alastair Hunter

Reporter (uncredited)

Paul Beradi

Technician (uncredited)

Bernard Bresslaw

Reporter (uncredited)

Patrick Halpin

Young Girl (uncredited)

Jane Dore

Reporter (uncredited)

Bill Nagy

Reporter (uncredited)

Terry Randall

Reporter (uncredited)

John Wilder

Jack the Barman

Tony Quinn

Reporter (uncredited)

Johnny Wyne

Thomas the Watchman (uncredited)

Leonard Sharp

Gatekeeper (uncredited)

Frank Sieman