Isle of Man Steam Packet Company England, Wales, Scotland and Ireland. Ports served included Liverpool, Silloth, Whitehaven, Holyhead, Ardrossan, Blackpool, Belfast and Dublin. Vessels and crews of the company were actively involved in both the First and Second World Wars. One vessel, , was attached to the British Grand Fleet and led the German High Seas Fleet into Scapa Flow in the Orkney Islands at the end of the First World War. Another vessel, "Viking", was converted to become a seaplane carrier, serving as . During the First World War, eleven out of a total fleet of fifteen Steam Packet ships were requisitioned by the Admiralty.
British home army in the First World War an invasion, going so far as to inform the War Office in February that the loss of so many of his troops to the field army overseas absolved him of the responsibility for home defence. Admiral John Fisher, a former First Sea Lord, was concerned about the increasing U-boat menace, and believed that the German war leader, Field Marshall Paul von Hindenburg, would be willing to risk the High Seas Fleet in an invasion attempt. The Admiralty regarded the risk as possible rather than probable, and guaranteed to be able to disrupt an enemy fleet within 32 to 36 hours