1940 the Second World War at Sea in Photographs

January 1940 saw the escalation of the sea war between Britain and Germany. U-boats would claim numerous casualties, including HMS Exmouth and all 135 of her crew on 21 January 1940. In February, Hitler ordered unrestricted submarine warfare, while HMS Cossack rescued crews of British ships sunk by the Graf Spee from the supply ship Altmark. An air raid on the naval base at Scapa Flow saw the first British civilian casualties of the war in March. Two invasions of Norway began in April, with the