Hitler's decision was made after consultation with Field Marshal von Rundstedt at his field headquarters on the morning of May 24. The decision was based on the advice of von Rundstedt, who wanted to preserve his motorised forces for the push on Paris, Hitler agreed, trusting in Goering's promise that the Luftwaffe would wipe out the pocket.

At the time it didn't look like a bad decision: confidence in the Luftwaffe's ability to destroy concentrated forces was at an all-time high, and no one expected the pocket to survive. The day the halt order was given Churchill's orders were for the perimeter forces to go down fighting, buying time for a French counter-offensive that was never likely. When the evacuation order was given two days later, the expectation was that perhaps 45,000 men would be rescued; the eventual total was 224,301 British soldiers - virtually the entire British Expeditionary Force - and 111,172 French and Belgian soldiers.

Kershaw, Ian Fateful Choices: Ten Decisions that Changed the World, 1940-1941