Battle of the Atlantic Kriegsmarine M4 4-rotor Enigma Bletchley Park
Elsewhere, recent British success in the Battle of the Atlantic was compromised by the Kriegsmarine's introduction of its M4 4-rotor Enigma, whose signals could not be deciphered by Bletchley Park for nearly a year. In the Far East, the news was much worse with Japanese advances in all theatres, especially at sea and in Malaya. At a press conference in Washington, Churchill had to play down his increasing doubts about the security of Singapore.
