1/2 Crown - Elizabeth II Battle of the Atlantic - You saved the land...

The Battle of the Atlantic ran for the entire length of the Second World War — the longest continuous military campaign of the conflict. Gibraltar's role was not peripheral: the Strait was the choke point through which Allied convoys had to pass, and the Rock housed the naval command coordinating much of the western Mediterranean escort operations. By 1942, U-boat losses were running catastrophically high for the Allies, with merchant tonnage sunk outpacing new construction until the tide finally shifted in May 1943.

The quoted phrase originates from Churchill's 1943 tribute to Merchant Navy crews, delivered after the Allies declared victory in the Atlantic campaign.