HMNB Portsmouth the military and naval units destined for Sword Beach on the Normandy coast as a part of Operation Overlord and the D-Day landings on 6 June 1944. Troops destined for each of the landing beaches left from Portsmouth aboard vessels such as the armed merchant cruisers HMCS "Prince Henry" and HMCS "Prince David", escorted by the Canadian destroyers HMCS "Algonquin" and "Sioux". The majority of the naval support for the operation left from Portsmouth, including the Mulberry Harbours. Boathouse 4 (built around the start of hostilities) contributed to the construction of landing craft and support vessels as well as more
Race to the Sea French Territorial divisions from Lens to Lille and on 5 October, Marwitz ordered the cavalry to advance westwards to Abbeville on the Channel coast and cut the railways leading south. At the end of 6 October, Falkenhayn terminated attempts by the 2nd Army to break through in Picardy. To the north, the I and II Cavalry corps attacked between Lens and Lille and were quickly forced back behind the Lorette Spur. Next day, the cavalry was attacked by the first troops of the French XXI Corps to arrive as they advanced eastwards from Béthune. The German 6th Army took Lille