After their devastating surprise attack on the unprepared French Navy anchored in Mers-el-Kébir near Oran on July 3rd, 1940, for September 23rd of that year the British and those French willing to continue fighting the Germans had planned another coup.
The goal of Operation Menace was the seizure of French West Africa including its capital, the strategic port of Dakar in modern Senegal, from pro-German colonial authorities loyal to Vichy France.
For that purpose, the British Royal Navy deployed an aircraft carrier, two battleships, five cruisers, ten destroyers and several transports with some 8,000 Anglo-French troops.
General Charles de Gaulle (1890-1970), leader of the Free French government in exile established in London on June 18th following the official request for an armistice by France in view of its fast defeat by Germany in World War II, was onboard.
De Gaulle had wrongfully predicted little, if any resistance by Admiral Marcel Landriau (1886-1962), commander of the Dakar naval base, and an immediate willingness to negotiate a peaceful handover by Governor Pierre Boisson (1884 -1948).
After the convoy arrived at the peninsula early in the morning, he quickly broadcasted a series of messages to those French he considered to be on the “wrong” side, but a boat with his representatives trying to enter the port was later fired upon. The propaganda leaflets dropped by Britain’s Fleet Air Arm (FAA) didn’t have the expected result either.
Before noon, Vichy ships trying to leave were given warning shots and returned to port, from where coastal batteries opened fire on the attackers. In consequence, the British warships fired back. An engagement between them and the Allied fleet continued for several hours.
The crews of Free French aircraft that attempted to land at the airport had been immediately been taken prisoners. An attempted landing by Free French marines was seen off in heavy fog by Senegalese infantry.
By dusk, the defenders remained determined and their guns mostly intact. In the late evening, British commander Admiral Andrew Cunningham (1883-1963) received the message from British Prime Minister Winston Churchill (1874 -1965) not to give up. Just before midnight the Allies demanded surrender, which was rejected four hours later.
On September 24th several vessels were hit on both sides and two Vichy submarines sunk, but no breakthrough was achieved. The garrison didn’t hold back at all.
By now, de Gaulle realized that he had underestimated the challenge. Far from swiftly switching sides, his fellow countrymen were putting up stiff resistance. A landing by the Free French right at Dakar no longer looked viable and to intensify the bombardment would have also risked civilian lives.
So he proposed Cunningham to drop landing forces further down the coast and march them back on the capital while maintaining a blockade, though failed to convince him.
September 25th began with renewed air attacks on the harbor and the dockyards, but most of the bombs missed to cause significant damage. While most of the Allied force suddenly retreated to Freetown in Sierra Leone, driven off by an isolated colonial force, the battleship in need of repair was towed back to the United Kingdom.
This unexpected outcome, although more symbolic than materialistic, undermined De Gaulle’s prestige, as he had assessed quite inaccurately the loyalties and steadfastness of those he wanted to win over.
Two years later, French West Africa would finally fall into Allied hands during Operation Torch (November 1942 8th-May 13th, 1943) following the invasion of French North Africa.
P.D.: During most of this short conflict, bombers of the Vichy Air Force (Armée de l’ Air de Vichy) based in North Africa and commanded by General Jean Charles Romatet (1893-1975) attacked Gibraltar, but with little success.