Battle of Britain Day 80. Despite rain and clouds over Southern England, Luftwaffe launches a series of daylight bombing raids. At 9 AM, 80 bombers &100 fighters cross Kent towards London. Most of the bombers are turned back near Maidstone & Tonbridge, but some get through to bomb London. At 11.20 AM, 25 bombers & 45 Me110s fly towards Bristol. They are intercepted, sparing the Bristol Aeroplane Company, but RAF Filton is bombed. At midday, 300 German aircraft (mostly fighters) again cross Kent towards London but they are engaged at 12.30 & turned back. At 3 PM, 80 bombers & 80 fighters again fly towards London. They are intercepted & dispersed but 20 aircraft bomb Central London. In another big victory for RAF, Luftwaffe loses 21 bombers and 34 fighters while RAF loses 27 fighters (13 pilots killed). Overnight, there is heavy bombing of London (from Dieppe and Le Havre), as well as attacks on Liverpool (from Cherbourg), Edinburgh (from Denmark), Birmingham & Nottingham.
Germany, Italy and Japan sign the Tripartite Pact, designed to keep USA out of the war. Each agrees to declare war on any country that joins the war against one of the others. As Japan is not currently at war with the Allies, this is a clear sign of their intent to become involved.
At 11.13 AM, U-31 sinks Norwegian MV Vestvard 300 miles West of Ireland (1 killed, 30 survivors escape in 1 lifeboats and make land October 1 near Galway, Ireland). In the same area at midnight, U-37 sinks Egyptian steamer Georges Mabro (all hands lost). After sailing 500 miles West from base at St-Nazaire, France, in 4 days, U-46 malfunctions and dives accidentally, killing Oberbootsmaat Heinrich Schenk and Matrosenobergefreiter Wilhelm Reh. The patrol is aborted and they return to St-Nazaire.
Minesweeper HMS Halcyon is badly damaged on a mine laid by German aircraft in the mouth of the River Tees, North England (several crew wounded). Halcyon will be out of service until July 1941.