Operation Barbarossa

Hitler launched his invasion of the Soviet Union on Sunday, 22 June 1941. It was no surprise to Churchill, who had known since early April, from Enigma decrypts at Bletchley Park, that the attack was imminent. He had tried to warn General Secretary Joseph Stalin via the British ambassador to Moscow, Stafford Cripps, but to no avail, as Stalin did not trust Churchill. The night before the attack, already intending an address to the nation, Churchill alluded to his hitherto anti-communist views by saying to Colville: "If Hitler invaded Hell, I would at least make a favorable reference to the Devil".