by Mihal Epirot
Churchill ordered this plan in May 1945, the proposed date was 1 July 1945, the massive numerical disadvantage, consideration of rearming German troops, rejection by military leaders (including Alan Brooke), and declassification in 1998.
In the spring of 1945, although marked by the fall of Berlin and the defeat of Nazism, behind the scenes of diplomacy a plan bordering on madness was hidden: Operation Unthinkable. While Zhukov’s and Konev’s Red Army consolidated its power in the heart of Germany, Winston Churchill began to view his former Soviet ally with growing terror. For the British Prime Minister, the disappearance of the common enemy had transformed Stalin into an existential threat to Western democracies, pushing him to plan a surprise attack scheduled for July 1, 1945.
The plan, declassified only in 1998, had ambitious and highly controversial objectives: to drive the Russians out of Berlin, liberate Prague and Vienna, and above all, resolve the ‘Polish impasse.’ Churchill dreamed of an Eastern Europe free from Russian influence and a Poland liberated from pro-Soviet puppet governments. However, the strategy developed by Brigadier Thompson seemed, as its name suggests, unthinkable: it envisaged deploying 47 Anglo-American divisions against more than 170 Soviet divisions, with the disturbing support of approximately 100,000 rearmed Wehrmacht and SS soldiers.
The War Cabinet and Field Marshal Alan Brooke rejected the operation, recognizing the impossibility of a land victory against the overwhelming numerical superiority of the Red Army and the serious political danger of rearming the Germans. Despite the veto, the information leaked through Soviet spies, prompting Stalin to reorganize his defenses in Germany as early as June 1945. Fortunately, Churchill’s idea remained confined to paper, sparing the world a third world war just as the wounds of the second were beginning to heal.”
Sources
The National Archives (UK). “Operation Unthinkable: Report by the Joint Planning Staff.” CAB 120/691, 22 May 1945. https://www.nationalarchives.gov.uk/education/resources/cold-war-on-file/operation-unthinkable/.
Walker, Jonathan. Operation Unthinkable: The Third World War – British Plans to Attack the Soviet Empire 1945. Stroud: The History Press, 2013.
Reynolds, David. “Operation Unthinkable.” In In Command of History: Churchill Fighting and Writing the Second World War. London: Allen Lane, 2004.
Pidgeon, Kyle Xander. “Operation Unthinkable and the Origins of the Cold War.” Webster Review of International History (2025). https://websterreview.lse.ac.uk/articles/101/files/687742ab6cfc0.pdf.
HistoryHit. “Operation Unthinkable: Churchill’s Postwar Contingency Plan.” April 21, 2023. https://www.historyhit.com/operation-unthinkable-churchills-postwar-contingency-plan/.
Primary Document Reference (Footnote):
Joint Planning Staff, “Operation Unthinkable,” 22 May 1945, CAB 120/691, The National Archives, Kew.
