On 3rd July, 1940, the Royal Navy under James Somerville arrived at Mers-el-Kébir and ordered the French forces to surrender or be attacked. After hours of unsuccessful negations Somerville gave orders for the British fleet to open fire on the French Navy. One battleship was sunk and two were seriously damaged. A total of 1,147 sailors were killed in the attack.
On 6th July the Ark Royal arrived and torpedoed the Dunkerque killing 150 more men. Its aircraft also delivered further attacks on Mers-el-Kébir.