Key point: The British and American alliance with Russia only lasted as long as Hitler.
In the spring of 1945, Winston Churchill asked his military chiefs to prepare a secret plan.
That was nothing new. The hyper-energetic Churchill was always coming up with plans, some clever and some crazy. But this plan was beyond all that.
Winston Churchill wanted a plan for Britain to invade the Soviet Union.
In early 1945, America was focused on finishing off Germany and then taking down Japan. But Churchill's gaze beheld a darkness descending upon Europe. What would happen with a Red Army occupying its heart? Stalin had already reneged on earlier agreements that Poland—the reason that Britain had gone to war in 1939—would be free. Instead the Polish government was packed with Soviet supporters while Polish resistance fighters ended up in NKVD prisons. Romania, Hungary and Czechoslovakia were under Soviet control, and Greece and Turkey appeared under threat. After Germany's inevitable surrender, the huge U.S. force in Europe would move to the Pacific.
Who would be left to stop the Russians?
Thus British planners devised “Operation Unthinkable,” an apt name for what would have been World War III. What could be a more unimaginable task then trying to devise some way for Britain—broke and exhausted after two world wars—from launching a preventive war to defeat the Soviet colossus?
Yet even if Great Britain was losing the “Great” by 1945, orders were orders, and military planners are accustomed to devising responses to the most unlikely contingencies. So they gamely went to work, and by 1945 had worked out a plan. The attack would begin on July 1, 1945, to allow operations before the winter weather arrived. They assumed that Soviet intelligence would detect Allied preparations and thus make an Operation Barbarossa–style surprise offensive impossible. Thus the Allies would have a tough fight right from the start.