Edward Judd (Lt. Cmdr. Tarlton)James Robertson Justice (RAdm. Rainbird)Laurence Payne (Lt. Seaton)Joachim Fuchsberger (Cmdr. Scheffler)Arthur O'Sullivan (Mike Fitzgerald)Albert Lieven (Capt. Neymarck)Robert Flemyng (Vice-Adm. Sir James Carver)Richard Carpenter (Lt. Haskins)Richard Thorp (Lt. Chatterton)Jeremy Hawk (Adm. Saintsbury)Robert Brown (Coxswain Drage)Frederick Jaeger (Lt. Hence)George Mikell (Lt. Remer)Peter Myers (Telegraphist Packshaw)Leslie Randall (Leading Seaman Donnithorne)Ewen Solon (Lt. Cmdr. Kirklees)Roberta Desti (3rd Officer Mather)Brian Peck (Able Seaman Winner)
During WWII, the British Royal Navy uses a captured German submarine to trick the enemy and protect their supply convoy.