What if?' history is a tricky game, but there is no doubt that the senior planners of D-Day - including Eisenhower and the British general Bernard Montgomery - believed that the Double Cross operation had played a pivotal role in the victory.

What if?' history is a tricky game, but there is no doubt that the senior planners of D-Day - including Eisenhower and the British general Bernard Montgomery - believed that the Double Cross operation had played a pivotal role in the victory.