In July 1940, the Royal Navy attacked a French fleet off the coast of Algeria, killing more than 1,200 sailors. This "hateful" incident move Winston Churchill to tears. Yet, writes Edward Abel Smith, in giving the operation the green light, the British PM may have won the Second World War
At just before 6pm on Wednesday 3 July 1940, the first shells were fired towards the coast of Algeria. Across the shimmering water of the harbour at Mers el-Kébir, the crews of a group of French warships had no idea what was coming. Earlier in the day, French sailors had been relaxing on deck. A bathing party had been ashore for a morning of recreation. It was, by all accounts, a perfectly ordinary day.
What followed was less than 10 minutes of ferocious shelling, the result of which was devastating. French battleship Bretagne took a direct hit, lurched forward and capsized in just minutes – the vast majority of the crew would not survive. Her sister ship, Provence, was ablaze. One of the most powerful battleships in the world, Dunkerque lay grounded, her hull torn open. In the oil-black water where the ships had been peacefully moored minutes before, bodies floated among the wreckage.
Rescue boats picked their way through the debris. Some survivors were so caked in oil that those trying to save them could find no grip – and so they were pulled from the water by their hair. The fleet's chaplain, Father de Gueuser, moved slowly through it all in a small rowboat, reciting prayers over objects he could not identify. He blessed them all, just in case.
It was less than 10 minutes of ferocious shelling, the result of which was devastating
In total, 1,297 French sailors were killed that afternoon. They were not killed by the Germans. They were not killed by the Italians. They were killed by the Royal Navy – acting on an order signed by Winston Churchill. The attack at Mers el-Kébir remains the deadliest clash between Britain and France since the battle of Waterloo, 125 years before. And it may also have been the decision that won the Second World War.
The world Churchill inherited
To understand why Churchill gave that order, it is important to understand the world as it looked from the Cabinet Room at 10 Downing Street in the summer of 1940. It was a world in freefall.
Churchill had been prime minister for 55 days. In that time, he had watched Italy throw in its lot with Hitler, adding 1.7 million soldiers, six battleships and 100 submarines to the Nazi cause. Churchill had overseen the evacuation of over 330,000 Allied troops from the beaches of Dunkirk – hailed as a miracle, though the miracle had left behind 700 tanks, 64,000 vehicles and 76,000 tonnes of ammunition on the sand. Britain's ability to fight a land war was, in practical terms, finished. Churchill inherited a RAF that only had around 650 serviceable aircraft.
To add to the predicament, most of western Europe had fallen. France – Britain's closest ally, the nation with whom Churchill had personally pleaded to keep fighting – had signed an armistice with Hitler on 22 June, in the same railway carriage, in the same forest clearing, where Germany had surrendered in 1918. Hitler's choice of location was deliberate. He wanted the humiliation to be absolute.
Across the Channel, Britain stood entirely alone. Even Hitler assumed Churchill would eventually come to the table and seek terms. Chief propagandist for the Nazi Party, Joseph Goebbels noted in his diary that the Führer wanted to give England “one last chance for peace”. Churchill had no intention of taking it – but he needed to prove that to the world, and most urgently to Washington.
The one military card Churchill still held was the Royal Navy. Britain remained, just about, the dominant naval power in the world – and through that dominance, in theory, it could still control the vital shipping lanes on which an island nation depended. However, the Royal Navy’s size would be overshadowed if Germany swallowed the French fleet into its own. Churchill was determined that would not happen.
The fleet that could change everything
France had the fourth-largest navy in the world – 800,000 tons of warships, seven battleships, 12 light cruisers, 71 destroyers, 78 submarines.
As France collapsed and sought armistice terms, Churchill appealed directly to French leaders not to let their fleet fall to Germany. He warned that to do so would “scarify their names for a thousand years of history”. His appeals went unheeded.
Churchill had confronted Admiral Darlan – commander-in-chief of the French navy – directly. “Darlan, I hope that you will never surrender the Fleet.” Darlan was emphatic: “There is no question of doing so. It would be contrary to our naval traditions and honour. We will never hand it over to Germany or Italy."
These were reassuring words. However, words were not enough. The armistice terms France had been offered were far more generous than expected – Hitler was being lenient, allowing the French to retain about two-fifths of their territory. The French negotiators knew that any further cooperation with Britain risked jeopardising their position. Darlan's promise was sincere in the moment. But Hitler could not be trusted to keep his promise. Germany's navy, the Kriegsmarine, was small – one of his genuine weaknesses. Adding even a fraction of the French fleet to it could shift the entire balance of the war at sea. Churchill could not afford to take Darlan at his word.
Late on the night of 2 July, Churchill sat with his First Lord of the Admiralty and First Sea Lord, debating whether to act. He had already received a letter from Vice Admiral Somerville, who was to command the operation, urging him in the strongest terms to avoid force. Churchill read the letter aloud and set it aside. Around half past midnight, Lord Beaverbrook – the newspaper magnate Churchill had drafted into the War Cabinet to transform aircraft production – was summoned to Downing Street. For an hour, Churchill walked him through the plan. Beaverbrook was unequivocal: attack was necessary. Germany would appropriate the French ships whether the French captains liked it or not. Britain's survival came first.
That was enough. Churchill authorised Operation Catapult – a simultaneous, co-ordinated attempt to seize or destroy French vessels across multiple locations. He ordered his admirals to prioritise the destruction of Dunkerque and Strasbourg, the two most powerful vessels in the French fleet posted at Mers el-Kébir.
After the admirals left at 2am, Churchill and Beaverbrook walked into the garden at the back of Downing Street. It was a blustery night, barely 14 degrees. As they talked, Beaverbrook saw tears in Churchill's eyes. “This is heartbreaking for me,” he said. He was convinced the decision was necessary. He also knew what it would cost.
Germany would appropriate the French ships whether the French captains liked it or not. Britain's survival came first
Twelve hours that changed history
The task of delivering the ultimatum fell to Captain Holland – nicknamed 'Hookey' for his badly misshapen nose, the Royal Navy's finest French speaker and a man who genuinely loved France. His appointment as envoy was, on the face of it, an inspired choice by Vice Admiral Somerville, as Holland was highly respected by the French naval leadership.
He was dispatched ahead of the main fleet in the destroyer HMS Foxhound, carrying four options for the French commander at Mers el-Kébir, Vice Admiral Gensoul. The French could sail their ships to Britain and fight on. They could sail to a port in the West Indies or America, to be disarmed for the duration. They could scuttle where they lay. Or they could hand the ships over to the British. What they could not do – under any circumstances – was allow a single vessel to fall into German hands. If none of the four options was accepted, the code word was ANVIL. Then the British would take matters into their own hands, using force to put the French warships out of action.
Gensoul was a proud and brooding patriot with a deep-seated suspicion of the British. He was acutely insulted that Captain Holland – a man three ranks his junior – had been sent with an ultimatum, rather than a senior officer for proper negotiation. He refused to meet Holland in person for hours. All the while he was not simply being stubborn – he was buying time, quietly rearming his fleet, waiting for darkness, preparing either to escape or to fight back.
Throughout the day, Churchill waited anxiously in the Cabinet Room at Downing Street, cigar in hand, receiving regular updates from Somerville. His orders had been clear – the matter had to be resolved before nightfall. As the hours ticked by, Somerville extended his deadlines repeatedly: 1330 hours, 1500, 1530, 1730. At one point Holland stopped his signaller mid-transmission, unable to bring himself to send the final ultimatum. He had not slept since 2 July.
A brief, agonising near-breakthrough came in the early afternoon. Gensoul finally agreed to receive Holland aboard Dunkerque. The two men talked. Gensoul appeared to soften. For a moment, a peaceful resolution seemed possible. But the clock had run out. Somerville's final deadline was 1730. Soon, Holland was back in his motor cutter, pulling away from Dunkerque's side.
As the guns of Force H opened fire 14 minutes later, Holland was still in the water between the two fleets. He watched as enormous columns of orange flame erupted from the harbour. He did not look away.
For a moment, a peaceful resolution seemed possible. But the clock had run out
War, alliance and the long shadow
The immediate aftermath was, for Churchill, one of the most charged moments of his entire premiership. In his memoir The Second World War, Volume II: Their Finest Hour, he would describe Mers el-Kébir as “a hateful decision, the most unnatural and painful in which I have ever been concerned. It was a Greek tragedy. But no act was ever more necessary for the life of Britain and for all that depended upon it.”
The attack poisoned Franco-British relations. Skirmishes between the two nations broke out in Dakar, Syria and Lebanon. Trust between Britain and France would not fully recover for years.
But in Washington, the reaction was everything Churchill had hoped for. For all the British PM’s soaring rhetoric about fighting on the beaches and never surrendering, President Franklin D Roosevelt had remained privately uncertain that Britain would hold. Words were one thing. Ordering the Royal Navy to destroy its closest ally's fleet – at a cost of nearly 1,300 lives – was another entirely. As Churchill's private secretary, John Colville, later recalled, one of Roosevelt's closest advisor, Harry Hopkins, told him directly: “It was Mers el-Kébir which convinced President Roosevelt, in spite of opinions to the contrary, that the British really would go on fighting – as Churchill had promised, if necessary for years, if necessary alone.”
Shortly afterwards, Roosevelt signed the Destroyers for Bases Agreement – 50 American destroyers transferred to Britain – the first decisive step on the road to American involvement in the war. Lend-Lease (a policy that enabled the US to provide Allied nations with food, oil and military equipment) followed. Then the US navy began escorting convoys. The groundwork for American entry was being laid, and Churchill always believed Mers el-Kébir was the moment that made it possible.
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The ultimate historical verdict came on 27 November 1942, when German troops occupied Toulon. The French navy scuttled its remaining ships – Strasbourg, which had been able to escape the British attacks at Mers el-Kébir, was among them – rather than let a single vessel fall into enemy hands.
“The voluntary destruction of the fleet at Toulon has just proved that I was right,” Darlan wrote defiantly to Churchill in December 1942, just a few days before the admiral’s assassination. In one sense, Darlan was not wrong – the French admirals had never intended to hand their ships to Germany. But would Hitler have seized them anyway?
What if Churchill had held back?
It is the great what-if of the early war. Had Churchill flinched – had he chosen to trust Darlan's promise, to give diplomacy more time, to hope for the best – the French fleet would almost certainly have remained intact through 1940 and into 1941.
Whether Germany would ultimately have seized it is unknowable. What is rather more knowable is what would not have happened: Roosevelt likely would not have been convinced that Britain was willing to fight on. Certainly not as soon as he did. The Destroyers for Bases Agreement might never have been signed. American support, when it came, might have come too late – or not at all. Without the naval convoys, the weapons, the men, it is very difficult to see how Britain would have survived the winter of 1940 and beyond.
History has largely judged Churchill's decision as correct – a brutal, sorrowful necessity at an impossible moment.
He called it a hateful decision. And he was right about that. But some decisions are both hateful and necessary, and the rarest quality in a leader is the willingness to make them anyway, in full knowledge of the cost, when the alternative is something worse. On the sweltering afternoon of 3 July 1940, in the harbour of a small Algerian port that almost nobody in Britain had heard of, Winston Churchill demonstrated that quality. It may well have saved Britain.
Edward Abel Smith is an author, feature writer, documentary maker and podcaster. His latest book is A Hateful Decision: Churchill’s Darkest Hour and the British Attack on the French Navy (Transworld, 2026)