In World War II, the greatest threat to the British navy is the German battleship Tirpitz. While anchored in a Norwegian fjord, it is impossible to attack by conventional means, so a plan is hatched for a special commando unit to attack it, using midget submarines to plant underwater explosives.
John Mills
as Commandant Fraser
John Gregson
as Lieutenant Alec Duffy
Donald Sinden
as Lieutenant Tom Corbett
James Robertson Justice
as Admiral Ryder
Michael Medwin
as Smart
Theodore Bikel
as German Officer
James Kenney
as Abercrombie
William Russell
as Ramsey
O.E. Hasse
as Captain of the Tirpitz
Lee Patterson
as Cox
Harry Towb
as McCleery
Cyril Chamberlain
as CPO Chubb
