What was the codename for the Allied evacuation from Dunkirk in 1940?

The codename for the Allied evacuation from Dunkirk in 1940 was Operation Dynamo. The British evacuation ran from 26 May to 4 June, as British, French, Belgian, Dutch, Polish, and other Allied troops were rescued from northern France.

The operation was directed from the naval headquarters beneath Dover Castle, where Vice Admiral Bertram Ramsay organized the evacuation. The name “Dynamo” referred to the room’s electrical dynamo. Royal Navy vessels and hundreds of civilian boats crossed the English Channel to carry soldiers away from the beaches and harbour.

Dunkirk was necessary after Germany’s rapid advance through the Low Countries and France trapped the British Expeditionary Force and several French formations. More than 338,000 Allied troops were evacuated, although much of their heavy equipment was abandoned.

A common mix-up is confusing Dynamo with Operation Overlord, the 1944 invasion of Normandy, or Operation Husky, the 1943 invasion of Sicily. Dunkirk was a withdrawal, not an invasion, yet it preserved a large Allied army for the battles still ahead.