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History

Our origins & WWI

British Signals Intelligence began in August 1914 following the outbreak of World War One

Signalmen using Morse code equipment in a Signal Exchange Station
© IWM (Q 128)

Over the course of the First World War, Signals Intelligence provided valuable insight into enemy plans, so much so that a peacetime cryptanalytical unit was formed in 1919 to continue the mission. Originally called the Government Code & Cypher School, it would later be renamed GCHQ.


The Birth of British Signals Intelligence

The Admiralty’s Room 40 and War Office's MI1(b) were naval and military intelligence units created at the start of WWI when it was realized that the interception of German radio traffic would give the country an advantage by allowing the UK to anticipate German plans.


The Birth of Signals Intelligence

When British Signals Intelligence began in 1914, the world was a very different place


The Impact of Signals Intelligence in WWI

Within a short period of the war breaking out, the UK had established a sophisticated signals intelligence capability against German radio traffic. This intelligence was used throughout the conflict to support all aspects of the British military and diplomatic war effort.

From 1916 it was used to help combat air raids and also offered valuable insight into the German naval movements ahead of the Battle of Jutland. In 1917 the secrets revealed by the interception of a German diplomatic telegram to Mexico contributed to drawing the US into the war. And in 1918 signals intelligence personnel operated on the front line during the major German counter-offensive.