World War II Day by Day: September 1940

The German Army conquered much of Western Europe in 1940 in a series of spectacular Blitzkrieg victories. German armor and aircraft attacked and defeated a succession of Allied armies in Scandinavia, France, and the Low Countries. Germany’s defeat in an aerial battle over Britain, however, saved that nation from any invasion. Britain’s survival now depended on North American aid. Meanwhile, the war widened, with Italian offensives in Africa and the Balkans.

2 September

Politics, Britain

Britain and the United States ratify a deal whereby 50 old destroyers, needed for convoy duties, are handed to Britain in exchange for bases in the Caribbean and Bermuda. Such exchanges will accustom the US public to aiding the Allied war effort.

3 September

Politics, Germany

The Operation Sealion landings are postponed from September 15 to the 21st. Two airborne divisions will be used to establish three bridgeheads on the south coast of England for an invasion force of nine divisions and 250 tanks.

7-30 September

Air War, Britain

Full-scale bombing raids on London - the ‘Blitz’ - begin with 500 bombers and 600 fighters. The RAF is initially surprised by the new German tactics, but adapts and concentrates its weakened forces against this threat. The bombing reaches its greatest intensity on the 15th, but the Luftwaffe is now suffering heavy losses, especially during its daylight raids on English cities, which are largely abandoned by the 30th. Bomber Command raids in France and the Low Countries destroy a tenth of the Nazi invasion barges on the14th-15th.

13-18 September

Africa, Egypt

An Italian force of 250,000 men under Marshal Rodolfo Graziani advances from Libya into neighboring Egypt against the British Western Desert Force of two divisions under General Sir Richard O’Connor. Graziani establishes fortified camps along a 50-mile (75-km) Front, while the British remain 75 miles (120km) to the east. British plans to attack Graziani are delayed as units are redirected to Crete and Greece, where an Italian invasion is feared.

15 September

Politics, Canada

Men aged between 21 and 24 are to be conscripted.

Politics, Soviet Union

Men aged between 19 and 20 are to be conscripted.

16-17 September

Sea War, Mediterranean

The British carrier Illustrious and battleship Valiant sink two Italian destroyers and two cargo ships at Benghazi, Libya.

Home Front, Britain

The Selective Service Bill permits the conscription of men aged between 21 and 35.

17 September

Politics, Germany

Adolf Hitler decides to suspend Operation Sealion after Germany’s failure to achieve aerial supremacy over southern England, while the General Staff inspects further plans for the invasion of the Soviet Union.

General Friedrich von Paulus, deputy chief of the Army General Staff, suggests offensives toward Leningrad, Kiev, and Moscow, with the latter being the main thrust.

20-22 September

Sea War, Atlantic

German U-boats launch their first successful ‘Wolf Pack’ operation, sinking 12 ships. In this tactic some 15-20 U-boats are deployed across the approaches to Britain. When a U-boat finds a convoy, it tracks the vessels and awaits the gathering of the entire ‘Wolf Pack’ for a combined attack.

21 September

Politics, Australia

Prime Minister Robert Menzies wins another general election for the United Australia Party, although Labor remains the largest individual party.

22 September

Far East, Indochina

Japanese forces enter the French colony after the powerless Vichy French authorities finally agree to the occupation. Some Vichy French resist the Japanese, who aim to prevent China obtaining supplies through the country.

23-25 September

Sea War, Africa

A British and Free French expedition, code-named Menace, attempts to occupy Dakar, French West Africa, with naval forces, including the British aircraft carrier Ark Royal, and 7900 troops. The Free French commander Charles de Gaulle fails to reach any agreement with the Vichy authorities, whose warships open fire. The Vichy French lose a destroyer and two submarines. Prime Minister Winston Churchill cancels Operation Menace after a Free French landing fails and British vessels suffer damage from Vichy French forces.

24-25 September

Air War, Mediterranean

Vichy France launches ineffective air raids on Gibraltar in retaliation for the British attack on Dakar.

25 September

Politics, Norway

Nazi sympathizer Vidkun Quisling, who proclaimed himself Norway’s leader following the German invasion, becomes head of the government. In reality Quisling remains a German puppet with limited authority.

27 September

Politics, Axis

Germany, Italy, and Japan agree a military, political, and economic alliance that pledges each country to fight any state that declares war on an Axis nation. The Tripartite Pact specifically aims to deter intervention by the United States in Europe or Asia.