UNITED KINGDOM: RAF Bomber Command: 4 Group (Whitley). Bombing - road/rail communications at Avesnes, Maubeuge, Aulnoye and La Capelle. 58 Sqn. Five aircraft. 4 bombed, one FTR. 77 Sqn. Ten aircraft. All bombed. 102 Sqn. Nine aircraft. One returned early U/S, eight bombed. One damaged by Flak.

R V Jones, a scientist with Air Intelligence, tells the government that intersecting radio beams could guide Luftwaffe bombers to their targets.

London: Sir Oswald Mosley and 33 other Fascists, including a Member of Parliament, were arrested today on the orders of the Home Secretary. Under Defence Regulation 18B he has powers to detain members of organisations which may be used for purposes prejudicial to national security.

Mosley was arrested on returning to his flat in Dolphin Square in London. After a lightning raid on the office of the British Union of Fascists in Great Smith Street, eight other leading members were arrested. The MP arrested is Captain A M Ramsay, member for Peebles and president of the anti-Semitic ‘Right Club’.

The male detainees were taken to Brixton Prison. Six women detainees were in Holloway Prison last night. An official of the Ministry of Health, a secret Fascist, was also arrested.

The first prototype of the Covenanter tank is delivered. (Erik Lund)

FRANCE: The Allies start to evacuate Boulogne as the Germans press on to the Channel ports.

Along the slopes of the Vimy Ridge Matilda tanks of the British 1st Army Tank Brigade check 7 Panzer Division.

On the night of 22/23, when Guderian had received news of Kleist’s permission to use his 10th Panzers, he decided that it should relieve the 1st at Calais, the capture of which was not urgent, in order to hurl this division against Dunkirk, as it was in a good position to attack that port. The most important consideration, in fact, was to cut the last vital artery of the Allied armies as soon as possible.

Therefore at 10 am, the 1st Panzers pivoted eastwards and advanced towards Dunkirk, using both the Bourbourgville and the Gravelines roads. During the day it was delayed by some centres of resistance, but mostly by the Allied air force, the superiority of which was for the first time reported by von Kleist to the OKH.

By the evening 1 Panzer has reached the Aa canal, between Holque and the coast, i.e. at the extreme right of the "canal line" which had been improvised only three days before by Lord Gort, and was very weakly held by mainly French troops from Gravelines to Saint-Momelin and the British south of Saint-Momelin.

Reinhardt’s corps arrives on the Aa canal between Saint-Omer and Aire, ready for a thrust to Cassel and Hazebrouck.

Boulogne: The British 20th Guards Brigade re-embarks on the destroyers which had brought it into Boulogne the day before. The French still hold out.

Calais: Attacked by 10 Panzer, it is defended by units of 21 Infantry Division (French) and British 30 Infantry Brigade, which had disembarked on the 22nd with a battalion of tanks.