'Lever' (i) was the British naval air attack on the French battle-cruiser Dunkerque in Mers el Kébir, the naval base near Oran in French Algeria, three days after the 'Catapult' gunfire attack of Vice Admiral Sir James Somerville’s Gibraltar-based Force 'H' on the French North African naval base (6 July 1940).

With escort for the fleet carrier Ark Royal provided by the battleship Valiant, the battle-cruiser Hood, the light cruisers Arethusa and Enterprise, and the destroyers Active, Escort, Fearless, Forester, Foxhound, Velox, Vidette, Vortigern and Wishart, the attack was delivered by torpedo-armed aircraft which took off from Ark Royal starting at 05.45 on 6 July: these six Fairey Swordfish warplanes were machines of No. 810 Squadron, and were escorted by six Blackburn Skua aircraft of Nos 800 and 803 Squadrons.

Attacking in several groups, the Swordfish aircraft scored a total of five torpedo hits on Dunkerque. These caused little in the way of major damage to the battle-cruiser, but hit the auxiliary patrol boat Terre Neuve, which was alongside the primary target, and the small auxiliary minelayer Esterel V, which was about 70 yards (65 m) from Dunkerque. Terre Neuve sank and its depth charges then detonated, the explosion tearing a large gash in the capital ship’s side as well as killing 210 more French sailors, and Esterel V was blown apart.