The Admiralty and the Strasbourg Rumour

In late June 1940, the British Admiralty lives in anguish over the fate of the French fleet. With the armistice signed, London fears that the powerful French ships, especially the modern Dunkerque-class vessels, will end up serving Germany or Italy, tipping the naval balance in the Mediterranean. The Dunkerque-class vessels are among the fastest in the world, and the thought of seeing them captured by the enemy haunts the British staff.

On the evening of 28 June, a note from naval intelligence reports that the battleship Strasbourg, anchored at Mers-el-Kébir, has apparently weighed anchor to join Toulon — or worse, to reach a port controlled by the Axis. The information cannot be verified immediately. The rumour reaches Churchill, who must decide the fate of the French fleet in the coming days. At the same time, the Royal Navy assembles Force H at Gibraltar and sets up Operation Catapult, intended to neutralise the French fleet in several ports at once.

The dilemma is that of intelligence in a time of crisis: act on unverified information at the risk of a serious mistake, or take the time to confirm at the risk of letting a threat slip. The officers' recommendation will weigh on the decision whether or not to attack Mers-el-Kébir.