200 German bombers and artillery pound the Citadel at Calais and German troops cross the canals forming the last Allied defensive line. At 4 PM, Brigadier Claude Nicholson surrenders at the Citadel. British losses are 300 killed, 200 wounded evacuated by boat and 3500 taken prisoner. Thousands of French and Belgian troops are captured. German losses are 750-800 killed or wounded.
Dunkirk. British War Cabinet sends a telegram to General Lord Gort authorizing the British Expeditionary Force withdrawal to Dunkirk. RAF Vice-Marshal Keith Park assigns 16 squadrons of No. 11 Group to protect the port. BEF’s retreat around Lille, France, leaves a gap in the Allied lines exposing the French left flank and Belgian right flank to the Walther von Reichenau's 6th Army. The Belgians fall back to the River Leie. The French 1st Army is essentially encircled.
Narvik. Anti-aircraft cruiser HMS Curlew sunk by German Ju-88 bombers (9 lives lost). The loss of Curlew’s aircraft warning radar outfit deprived the Allies of early warnings of incoming aircraft. http://www.naval-history.net/Photo06clCurlewNPIngoBauernfiend.jpg
U-13 and U-48 leave dock at Kiel to join the growing fleet attacking Allied shipping around the British Isles.