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
Scuttling of the French fleet at Toulon the French fleet would be largely disarmed and confined to its harbours, under French control. The Allies were concerned that the fleet, which included some of the most advanced warships of the time, might fall into enemy hands and so the British attacked the French Fleet at Mers-el-Kebir on 3 July 1940 and at the Battle of Dakar on 23 September 1940. On 8 November 1942 the Allies invaded French North Africa (Operation Torch). It may be that General Dwight Eisenhower, with the support of President of the United States Franklin D. Roosevelt and British Prime Minister Winston Churchill, made