Attack on Mers - el - Kébir The Attack on Mers - el - Kébir , part of Operation Catapult and also known as the Battle of Mers - el - Kébir , was a British Navy bombardment of the French Navy at its base at Mers - el - Kébir on the coast of what was then French Algeria on 3 July 1940 . A British naval task force attacked the French fleet , which was at anchor and not expecting an assault from the United Kingdom , France ' s former ally . The attack resulted in the deaths of 1 , 297 French servicemen , the sinking of a battleship and the damaging of five other ships . France and the United Kingdom were not at war but France had surrendered to Germany , and the UK feared the French fleet would end up as a part of the German Navy , a fate that would greatly increase the Kriegsmarine ' s size and combat ability . Although French Admiral François Darlan had assured Winston Churchill the fleet would not fall into German possession , the British acted upon the assumption that Darlan ' s promises were insufficient guarantees . The attack remains controversial to this day , and created much rancour between the United Kingdom and France , but it also demonstrated to the world and to the United States in particular , Britain ' s commitment to continue the war with Germany at all costs and without allies if need be . Background . In 1940 , after the Fall of France and the armistice between France and Nazi Germany , the United Kingdom became concerned about the possibility that the Germans would acquire control of the French fleet . The combined French and German naval forces would mean that the balance of power at sea might tip in Germany ' s favour , threatening Britain ' s ability to receive raw materials from across the Atlantic and its communications with the rest of its Empire . The British government feared the possibility despite the fact that the Armistice terms at Article 8 paragraph 2 stated that the German government " solemnly and firmly declared that it had no intention of making demands regarding the French fleet during the peace negotiations " and similar terms existed in the armistice with Italy . Furthermore , on 24 June , Admiral Darlan had given assurances to Churchill against such a possibility ( a later German attempt , made in violation of the Armistice terms , resulted in the French fleet scuttling itself in Toulon in 1942 ) . Winston Churchill ordered that the French Navy ( " Marine Nationale " ) should either join forces with the British Royal Navy or be neutralised in some way to prevent the ships from falling into German or Italian hands . The French fleet was widely dispersed . Some vessels were in port in France ; others had escaped from France to British - controlled ports , mainly in Britain and Alexandria , Egypt . Operation Catapult was to take the French ships into British control or destroy them . In the first stage , the French ships in the British ports of Plymouth and Portsmouth were simply boarded on the night of 3 July 1940 . The only resistance came from the French submarine " Surcouf " , then the largest submarine in the world , which had sought refuge in Portsmouth in June 1940 following the German invasion of France . The submarine ' s crew resisted the boarding , and three Royal Navy personnel , including two officers , were killed . A French sailor was also killed . Other ships captured included two obsolete battleship s , " Paris " and " Courbet " , the destroyer s " Triomphant " and " Léopard " , eight torpedo boat s , five submarines and a number of less important ships . Many – including " Surcouf " – went on to be used by the Free French forces . Some sailors joined the Free French while others were repatriated to France . The attack on the French vessels at port sowed anger amongst the French towards the British and increased tension between Churchill and the leader of the Free French Forces , Charles de Gaulle . Prelude . Ultimatum . The most powerful concentration of French warships at the time was the squadron at the port of Mers - el - Kébir in French Algeria . This consisted of the World - War - I - era battleships " Provence " and " Bretagne " , the modern battleships ( or battlecruisers ) " Dunkerque " and " Strasbourg " , the seaplane tender " Commandant Teste , " and six destroyers under the command of Admiral Marcel - Bruno Gensoul . British Admiral James Somerville of Force H , based in Gibraltar , was ordered to deliver an ultimatum to the French , stating : Somerville did not present the ultimatum personally . Instead , this duty fell to the French - speaking Captain Cedric Holland , commanding officer of the carrier HMS " Ark Royal " . Admiral Gensoul , affronted that negotiations were not being conducted by a senior officer , sent his lieutenant , Bernard Dufay , which led to much delay and confusion . As negotiations dragged on , it became clear that neither side was likely to give way . French Navy Minister Admiral Darlan never received the full text of the British ultimatum from Admiral Gensoul , most significantly with regard to the option of removing the fleet to American waters , an option that formed part of the orders Darlan gave to Gensoul , to be followed should a foreign power attempt to seize the ships under his command . Attack . The British force consisted of the battlecruiser HMS " Hood " , battleships HMS " Valiant " and " Resolution " , and the aircraft carrier HMS " Ark Royal " , plus an escort of cruisers and destroyers . Despite the approximate equivalence of force , the British had several decisive advantages . The French fleet was anchored in a narrow harbour and despite the unequivocal terms of the ultimatum , did not expect an attack and was not fully prepared for battle . The main armament of the " Dunkerque " and " Strasbourg " was grouped on their bows and could not immediately be brought to bear . The British capital ships , with their guns , also fired a heavier broadside than the French ones . Before negotiations were formally terminated , British Fairey Swordfish planes escorted by obsolete Blackburn Skua s were dispatched from the " Ark Royal " to drop magnetic mines in the path of the French ships ' route to sea . This force was intercepted by French Curtiss H - 75 fighters . One of the Skuas was shot down by French fighters and crashed into the sea , killing its two - man crew , the only British fatalities in the action . A short while later , on Churchill ' s instructions , the British ships opened fire against the French . The British opened fire at extreme range on 3 July 1940 at 17 : 54 . The French eventually replied but ineffectively . The third salvo from the British force and the first to hit resulted in a magazine explosion aboard " Bretagne " , which sank with 977 of her crew dead at 18 : 09 . After some thirty salvos , the French ships stopped firing . Meanwhile , the British force altered their course to avoid fire from the French coastal forts . " Provence " , " Dunkerque " and the destroyer " Mogador " were damaged and run aground by their crews . " Strasbourg " managed to escape with four destroyers . As these five ships made for the open seas , they came under attack from a flight of bomb - armed Swordfish from " Ark Royal " . The French ships responded with anti - aircraft fire and shot down two of them , and their crews were rescued by the destroyer HMS " Wrestler " . The bombing attack had little effect and Somerville ordered his forces to begin pursuing at 18 : 43 . The British cruisers " Arethusa " and " Enterprise " reported engaging a French destroyer . At 20 : 20 , Somerville called off the pursuit , feeling that his ships were ill - deployed for a night engagement . After weathering another Swordfish attack at 20 : 55 without damage , " Strasbourg " reached the French port of Toulon on 4 July . Subsequently , on 4 July , the British submarine HMS " Pandora " sank the French " aviso " ( gunboat ) " Rigault de Genouilly " , sailing from Oran . That night , French Air Force bombers carried out a retaliatory raid against the British fleet at Gibraltar to minimal effect . Since the British believed that damage to " Dunkerque " and " Provence " was not very serious , British Fairey Swordfish aircraft from " Ark Royal " raided Mers - el - Kebir the morning of 6 July . One torpedo hit the patrol boat " Terre - Neuve " , which was moored alongside " Dunkerque " and was carrying a supply of depth charge s . " Terre - Neuve " quickly sank and its charges triggered a large explosion , causing serious damage to " Dunkerque " . The last phase of Operation Catapult was an attack on 8 July by aircraft from the carrier HMS " Hermes " against the French battleship " Richelieu " , at Dakar . In response to the actions at Mers - el - Kébir and Dakar , the French Air Force launched retaliatory bombing raids on British targets in Gibraltar , including a half - hearted attack on 14 July when many bombs landed in the sea , and heavier raids on 24 and 25 September . Aftermath . At Mers - el - Kébir , 1 , 297 French sailors were killed and about 350 were wounded . Two British aircrew were also killed . Relations between Britain and France were severely strained for some time and the Germans enjoyed a propaganda coup . British Admiral Somerville was not enthusiastic about the action , saying that it was " . . . the biggest political blunder of modern times and will rouse the whole world against us . . . we all feel thoroughly ashamed . . . " Although it did rekindle anglophobic feelings in France , the action demonstrated Britain ' s resolve to continue the war alone and rallied the British Conservative Party around Churchill ( although Prime Minister Churchill was not party leader ) . Churchill later declared the action meant that for " high government circles in the United States . . . there was no more talk of Britain giving in . " Harold Nicolson reported the House of Commons to have been " fortified " by Churchill ' s report of the action . The French ships in Alexandria under command of Admiral René - Emile Godfroy , including the old battleship " Lorraine " and four cruiser s , were blockaded by the British in port on 3 July and offered the same terms as at Mers - el - Kébir . After delicate negotiations , conducted on the part of the British by Admiral Cunningham , the French Admiral agreed on 7 July to disarm his fleet and stay in port until the end of the war . They stayed there until they eventually joined the Allies in 1943 . The ships " Dunkerque " , " Provence " and " Mogador " were partially repaired and sailed back to Toulon . In early June 1940 , about 13 , 500 civilians had been evacuated from Gibraltar to Casablanca in French Morocco . Following the capitulation of the French to the Germans , and the attack on Mers - el - Kébir , the Vichy government found their presence an embarrassment . Later in June , 15 British cargo vessels arrived in Casablanca under Commodore Crichton , repatriating 15 , 000 French servicemen who had been rescued from Dunkirk . Once their French servicemen had disembarked , the ships were interned until they agreed to take away all the evacuees . ( See : Military history of Gibraltar during World War II ) . On 27 November 1942 , the Germans attempted to capture the French fleet based at Toulon as part of " Case Anton " , the military occupation of Vichy France by Germany . All ships of any military value were scuttled by the French before the arrival of German troops , notably " Dunkerque " and " Strasbourg " . For many in the French Navy this was a final proof that there had never been a question of their ships ending up in German hands and that the British action at Mers - el - Kébir had been an unnecessary betrayal . Within days Churchill received a letter from Admiral Darlan , in which he wrote ; " Prime Minister you said to me ' I hope you will never surrender the fleet ' . I replied , ' There is no question of doing so ' . It seems to me you did not believe my word . The destruction of the fleet at Toulon has just proved that I was right . " Casualties . French casualties in the action were distributed thus : Two British servicemen were also killed .