Operation Compass. 4th Armoured Brigade captures the Italian camp at Sidi Omar, which was leapfrogged in the rush into Libya to surround Bardia. They attack from the South and West, while the Italian artillery is facing East. The battle lasts 10 minutes (50 Italians killed, 900 taken prisoner).
At 7.50 PM off Cape Juby, Morocco, U-37 stops wooden Spanish steamer San Carlos with 1 torpedo and then tries to sink her with 21 rounds from the deck gun (1 killed). German sailors, rowing over to place scuttling charges, notice that the shells did not penetrate the wooden hull. 15 crew and 13 passengers abandon ship in 2 lifeboats.
British submarine HMS Truant sinks Italian tanker Bonzo in the Ionian Sea 2 miles off the coast of Calabria in the toe of Italy.
Overnight, RAF drops 100 tons of high explosive bombs and 14,000 incendiary canisters on Mannheim, Germany, in retaliation for the firebombing of Coventry on November 14. 8 pathfinder bombers miss the city center with incendiary canisters, causing most of the other bombers to miss the target (34 civilians killed, 81 injured). Learning from this failure, RAF develops the concept of "bomber stream" to drop the maximum amount of bombs in the smallest area over the shortest time.