The British planned to start World War III by invading Russia with the German army

With the dust still settling after the end of World War II in Europe, British Prime Minister Winston Churchill set his sights on the next threat to Western Democracy: the Soviet Union.

Churchill was a dedicated anti-Communist. Even before the war's end, the British PM expanded his anti-Communist rhetoric. He would later employ the same anti-Stalinist zeal in his public comments to people living inside the Iron Curtain (a term he coined in a 1946 speech).

The Prime Minister's 1946 speech argued the Soviets were determined to expand their influence across Europe and into Asia – a conclusion U.S. President Harry S. Truman also held.

So it makes sense that Churchill would ask his War Cabinet to draw up a plan that would "impose upon Russia the will of the United States and the British Empire," as Rakesh Krishnan Simha of Russia India Report writes.

This essentially meant Churchill was ready to start World War III.

Dubbed "Unthinkable" by Britain's General Staff, the plan called for American, British, and Polish troops — as well as soldiers from the newly-defeated Wehrmacht — to completely surprise the Soviets from the Baltic to the Mediterranean.

The differential in land forces between the West and the Soviet Union could not be offset by the air and naval superiority the Americans and British would have. The West just could not muster the manpower to match the Soviets. Churchill's Defence Minister warned him that a quick victory would be "beyond our power" and that they should be prepared for "a long, protracted war against heavy odds."

Manpower wasn't the only issue. The Defence Minister's plans relied on American allies — and the Pacific War was still in full swing. The United States was preparing for the invasion of mainland Japan. The rest of Europe was in tatters and could not assist the British in their efforts.

Then there was the question of how to defend the British Isles. The Russians could not mount the same submarine threat the Germans did during World War II. And the British Defence Ministry concluded the Russians certainly couldn't launch an invasion from the sea.

But rocket attacks were a different challenge altogether. British planners were well aware of this threat and included it in the report to Churchill. Once the Russians began making these weapons en masse, the British expected a "far heavier scale of attack than the Germans were able to develop and no way of effectively reducing this."

With Russian superiority in mainland Europe, the hypothetical rocket-based devastation of the British Isles in the scenario, and the insistence of President Truman that the United States would not participate, Churchill shelved the idea of starting World War III forever.