German Admiralty Declaration, 4 February 1915

This communication from Germany, forbidding all merchant shipping traffic in British waters, opened the first wave of: "unrestricted" submarine warfare:

All the waters surrounding Great Britain and Ireland, including the whole of the English Channel, are hereby declared to be a war zone. From February 18 onwards every enemy merchant vessel found within this war zone will be destroyed without it always being possible to avoid danger to the crews and passengers.

Neutral ships will also be exposed to danger in the war zone, as, in view of the misue of neutral flags ordered on January 31 by the British Government, and owing to unforeseen incidents to which naval warfare is liable, it is impossible to avoid attacks being made on neutral ships in mistake for those of the enemy.

Navigation to the north of the Shetlands, in the eastern parts of the North Sea and through a zone at least thirty nautical miles wide along the Dutch coast is not exposed to danger.

Translated from the Reichsanzeiger, February 4th, 1915,
quoted on pages 260-261 of Naval Operations volume II, by Sir Julian S. Corbett (Battery Press reprint).