John Mills as Lt. Cmdr. Armstrong

Richard Attenborough as Stoker Snipe

Nigel Patrick as Lt. Manson

George Cole as ERA Marks

Bernard Lee as Cmdr. Gates

Peter Hammond as Sub-Lt. Oakley

Andrew Crawford as Sub-Lt. J. McFee

Michael Brennan as CPO Barlow

Wylie Watson as

Helen Cherry as

Lana Morris as

Victor Maddern as

Kenneth More as

Zena Marshall as

James Hayter as

Frank Coburn as Leading Seaman Brough

Roddy McMillan as Leading Seaman Andrews

Jack Stewart as Leading Seaman Kelly

George Thorpe as Capt. Fenton

Alastair Hunter as Capt. Jenner