Italian Front: French Tenth Army C-in-C Fayolle informs Foch that Italians ‘had recovered their spirit and wanted to fight’.
Trentino: Conrad’s final attempt to break through before winter snows, promises soldiers winter at Bassano in plains below and Christmas Mass in Venice. After hurricane shelling including gas (by 550 guns) Austrian Eleventh Army captures Col del Rosso (4183ft), Mt Melago and 3 other features in 2-mile advance, claims 9,000 PoWs until December 24.
Irish Sea: Armed boarding steamer HMS Stephen Furness (101 lives lost) sunk by U-boat.
North Sea: 3 Harwich Force destroyers on Dutch convoy duty (Torrent, Surprise and Tornado) sink on German minefield north of Maas Light Buoy, 252 lives lost. Flotilla leader Valkyri gets home with broken back. Surviving destroyer Radiant rescues survivors.
Germany: Kaiser, visiting Second Army on Western Front, says 1917 proof that God an ally of German people.
France: Anglo-French Paris Convention on spheres of influence in Southern Russia (British War Cabinet approve on December 26).