It was Operation Unthinkable: Churchill's "impossible" plan to start World War 3
In 1945, as Europe celebrated peace, Winston Churchill quietly asked his generals to plan an attack on the Soviet Union. But how close was Britain to an immediate and consecutive war?
In the summer of 1945, Europe lay in ruins.
But for the first time in close to a decade, the continent was contemplating the prospect of peace. Hitler was dead, the Nazi high command had collapsed, and while the war raged on in the Pacific, bombs had at least finished dropping across Europe. It was a fresh and uneasy peace – but it was still a peace.
But even as celebrations were filling the streets of Europe’s great cities, British prime minister Winston Churchill was already considering another conflict.
At Churchill’s request, the British chiefs of staff had drafted a proposal codenamed Operation Unthinkable. Its goal was immense: a plan to drive the Red Army out of eastern Europe and restore the independence of the nations that had now fallen under Soviet control. Within weeks of the Second World War ending, Britain was already assessing the possibility of a third.
It was, as its name implied, almost inconceivable. And yet, Churchill insisted on seeing the plans. Speaking on the HistoryExtra podcast, historian Tim Bouverie explained how the idea developed.
From WW2 allies to adversaries
During the war, Britain, the United States and the Soviet Union had fought together against Nazi Germany. But their alliance was built on a pragmatic necessity rather than trust, or a sense of shared politics. By the time of the Yalta conference in February 1945, the cracks were already showing.
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At Yalta, Churchill, US president Franklin D Roosevelt and Soviet leader Joseph Stalin agreed on a postwar settlement for Europe, including a promise that liberated countries would hold free elections. Yet, as Bouverie explains, those promises began to crumble almost immediately.
“In the months following the Yalta agreement, Roosevelt was bombarded with messages from Churchill,” says Bouverie. “He gave details of how the Soviets were breaking the Yalta accords, how they were refusing to allow Allied observers into eastern Europe, how Stalin was dragging his feet on the exchange of prisoners of war, how he was progressing his plans to dominate these countries by force.”
While Roosevelt still hoped for cooperation, Churchill grew increasingly alarmed as Soviet control expanded through Poland, Romania and the Balkans. The uneasy alliance that had won the war was quickly hardening into mistrust.
The ‘percentages deal’
But Churchill’s suspicion of Stalin had predated Yalta.
“[During] Churchill’s mission to Moscow in October 1944, he came up with the infamous ‘percentages deal’ with Stalin over how the British and the Soviets were going to divide influence in the Balkans,” says Bouverie.
On a scrap of paper, Churchill jotted down rough proportions of influence: 90 per cent Soviet in Romania, 90 per cent British in Greece, and equal shares elsewhere. Stalin ticked the paper and passed it back. Even if he couldn’t stop Soviet domination outright, Churchill at least hoped to provide some limit to it.
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But by early 1945, it was clear Stalin intended to keep what he had taken. Churchill’s appeals to Roosevelt for a firmer response went largely ignored. It was out of that frustration that he came up with a more drastic idea.
Planning the impossible
In the spring of 1945, as Soviet troops rolled towards Berlin (doing so more quickly than the British and Americans had expected) they consolidated control over eastern Europe. “[It was then that Churchill] asked his chiefs of staff to look at the military feasibility of driving back the Red Army to the Soviet Union’s supposed natural frontiers; to where they were before the Molotov–Ribbentrop Pact of August 1939.”
The proposal envisioned British and American forces (and, controversially, rearmed German soldiers) launching a surprise offensive to push Soviet troops east. The chiefs of staff produced a preliminary report, codenaming the plan Operation Unthinkable. Its stated aim was to compel Stalin to accept a limitation to Soviet boundaries, but it would have meant an Anglo-American war against their recent ally within weeks of victory in Europe.
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Why it could never happen
Churchill’s advisers quickly concluded that Operation Unthinkable was impossible on every level.
“It was unthinkable for two reasons,” says Bouverie, “and these are reasons which surely Churchill knew.”
Militarily, the Red Army was vast. It outnumbered the Allied forces several times over, occupying most of eastern and central Europe. Even if an attack succeeded in Poland, Stalin could retreat deep into Russian territory, forcing the Allies into a long, unwinnable campaign. “Suddenly it wouldn’t have been the Wehrmacht freezing to death outside Moscow,” Bouverie notes, “but the British and the Americans.”
Politically, the idea was even more untenable. “The British and American publics had been fed on a pro-Soviet, pro-Red Army propaganda diet for the last three years,” Bouverie explains. “[Stalin] was Uncle Joe; these were our comrades-in-arms.”
To persuade exhausted soldiers and civilians to fight again, in the harshest of fronts, was unimaginable.
Churchill’s fears, and the Cold War to come
Operation Unthinkable was quietly shelved by June 1945. A month later, Churchill was voted out of office in the general election that brought Clement Attlee’s Labour government to power.
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Still, the episode revealed how profoundly Churchill distrusted Stalin and anticipated the coming divide in Europe. “From 1943 onwards,” Bouverie notes, “Churchill was increasingly obsessed with trying to save as much of eastern Europe as he could from the USSR’s domination and from communism.”
But his concerns, for all they foreshadowed the Cold War, didn’t matter.
“The idea of asking the British and the American people to engage in another conflict – against an emerging superpower, after five years of war to defeat Hitlerite Germany – was completely and utterly unthinkable.”
Tim Bouverie was speaking to Danny Bird on the HistoryExtra podcast. Listen to the full conversation.
Authors
James Osborne is a digital content producer at HistoryExtra where he writes, researches, and edits articles, while also conducting the occasional interview