The Northern Patrol was a Royal Navy operation of the First World War operating around Scotland and the North Sea. The Patrol existed to form part of the British "distant" blockade of Germany. It was to prevent German warships passing from the North Sea into the Atlantic Ocean and to check merchant ships were not carrying trade with Germany. The units of the Northern Patrol were the 10th Cruiser Squadron later supplanted by armed merchant cruisers which had better sea-keeping.