Operation Unthinkable was the name given to two related possible future war plans developed by the British Chiefs of Staff Committee against the Soviet Union in 1945. The plans were never implemented. The creation of the plans was ordered by British Prime Minister Winston Churchill in May 1945 and developed by the British Armed Forces' Joint Planning Staff in May 1945 at the end of World War II in Europe.

One plan assumed a surprise attack on the Soviet forces stationed in Germany to impose "the will of the United States and British Empire upon Russia". The same code name was thereafter reused instead for a second, marginally-related plan, a hypothetical defensive scenario by which the British were to defend against a Soviet drive towards the North Sea and the Atlantic Ocean after the withdrawal of the American forces from the Continent.

The study became the first Cold War-era contingency plan for war against the USSR. Both plans were top secret and were not made public until 1998, although Soviet spy Guy Burgess had passed on details to Soviet intelligence at the time.

Operations

Offensive

The initial primary goal of the operation was declared as "to impose upon Russia the will of the United States and the British Empire. Even though 'the will' of these two countries may be defined as no more than a square deal for Poland, that does not necessarily limit the military commitment". Most of the offensive operation would have been performed by American and British forces, as well as Polish forces and as many as 10 divisions of the German Army, remobilised from prisoner-of-war status. Any quick success would be caused by surprise alone. If a quick success could not be obtained before the beginning of winter, the assessment was that the Allies would be committed to a protracted total war. In the report of 22 May 1945, an offensive operation was deemed "hazardous".

The following table is based on Allied estimates at the time of the planning of Operation Unthinkable.

{|class="wikitable" style="text-align: right;"

|+ Projected balance in Western Europe by Allied estimates, 1 July 1945

|-

!

! colspan="1" style="background: #E6EEFF;" | Allied

! colspan="1" style="background: #FFE6E6;" | Soviet

! Ratio

|-

!Infantry divisions

| style="background: #E6EEFF;" | 80

| style="background: #FFE6E6;" | 228

| style="background: #FFE6E6;" | 1 : 2.85

|-

!Armored divisions

| style="background: #E6EEFF;" | 23

| style="background: #FFE6E6;" | 36

| style="background: #FFE6E6;" | 1 : 1.57

|-

!Tactical aircraft

| style="background: #E6EEFF;" | 6,048

| style="background: #FFE6E6;" | 11,802

| style="background: #FFE6E6;" | 1 : 1.95

|-

!Strategic aircraft

| style="background: #E6EEFF;" | 2,750

| style="background: #FFE6E6;" | 960

| style="background: #E6EEFF;" | 2.86 : 1

|-

|}

Defensive

In response to an instruction by Churchill of 10 June 1945, a follow-up report was written on "what measures would be required to ensure the security of the British Isles in the event of war with Russia in the near future".

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Bibliography

  • Hines, Sam. Operation Unthinkable. Its significance in the development of the Cold War (GRIN Verlag, 2016).
  • Norton-Taylor, Richard (2 October 1998) "Churchill plotted invasion of Russia" The Guardian
  • Ruane, Kevin (2016) Churchill and the Bomb in War and Cold War London: Bloomsbury Academic
  • Julian Lewis: Changing Direction: British Military Planning for Post-war Strategic Defence, 2nd edn., Routledge, 2008, pp.xxx-xl ()
  • Operation Unthinkable: Churchill's plan to start World War III