On 3 July 1940, the Royal Navy opened fire on French warships at Mers-el-Kébir in Algeria. Britain and France had fought as allies against Germany, but France had signed an armistice less than two weeks earlier.

The French Navy was one of the largest in the world. Its modern battleships could alter the balance of naval power if Germany gained control of them. French commanders insisted that they would never surrender their ships. Winston Churchill and the War Cabinet decided that these assurances were insufficient.

Admiral James Somerville sailed from Gibraltar with Force H. At Mers-el-Kébir, he delivered an ultimatum to Admiral Marcel Gensoul. The French ships could join Britain, sail to a British port, disarm or move beyond German reach. If Gensoul refused, Somerville was ordered to destroy them.

The negotiations lasted for several hours. Protocol caused delays, and Gensoul objected to dealing with an officer junior to him. The French regarded the ultimatum as an insult. The British feared that further delay might allow the ships to escape.

Somerville did not want to attack, but his orders left little room once the deadline expired. Shortly before six in the evening, the British force opened fire.

The French ships were moored in a position that made an effective response difficult. The battleship *Bretagne* exploded and sank. *Dunkerque* and *Provence* were damaged. The fast battleship *Strasbourg* escaped with several destroyers and reached Toulon.

About 1,300 French sailors were killed. British losses were slight.

The operation reduced the immediate threat posed by the ships at Mers-el-Kébir, but it caused deep anger in France. The Vichy government broke diplomatic relations with Britain, and the attack remained a grievance long after the war.

The French fleet was not later handed intact to Germany. When German forces tried to seize the ships at Toulon in November 1942, French crews scuttled them. This supported the French claim that their assurances in 1940 had been genuine. However, the British government could not know how events would develop.

Britain had removed one possible danger by attacking men who had fought beside it only weeks earlier.