We've seen it time and time again in this war. Supposed Allies arguing with each other instead of fighting the enemy. But when SOE and MI6 begin vying for leadership of Britain's secret war, it's more than cross words. Now there are lives at stake.

We've already seen the power of signals intelligence. Churchill loves being fed information from MI6's Ultra. Now it brings a vengeance for his American allies. They manage to bag the scourge of Pearl Harbor, C-in-C of the Imperial Japanese Navy, Admiral Isoroku Yamamoto.