Admiralty sends the "warning telegram" to the fleets

On the morning of 29 July 1914 the British government, under pressure from the First Lord of the Admiralty, Winston Churchill, agreed to begin the so-called precautionary period. The signal to set it in motion was the pre-arranged “warning telegram”. That same day the Admiralty sent it to all formations of the Royal Navy.

The telegram was neither an order to start a war nor a proclamation of mobilisation. It was a short, coded signal that set in motion procedures prepared in advance. From the moment they received it, the commanders of fleets and squadrons, both in home waters and on the distant stations of the British Empire, were to treat the situation as an immediate threat of war and prepare their ships for action in accordance with the war plans.

The decision came when the First Fleet was already on its way north. That same day it sailed from Portland, and during the night of 29–30 July it passed through the Strait of Dover without lights, heading for its war base at Scapa Flow. The warning telegram, however, applied to the whole Royal Navy, not just the main fleet.

For several days Churchill had been steadily preparing the navy for war before the government had decided on it. The halting of the fleet’s dispersal on 26 July, the move to Scapa Flow and the warning telegram of 29 July meant that the Royal Navy, the largest fleet in the world, was ready for action before Great Britain formally entered the war.