The Secret Service Bureau was started in 1909 as an attempt to combat Imperial Germany’s espionage operations in the UK. The MI5’s website has a section relating to the origins of the organisation and its activities in the run up to 1914 and during the war as German spies sought political, military and industrial secrets.
It also has a detailed history of the organisation’s work throughout the 20th century.
To learn more about MI5’s WW1 history, click here.
Images courtesy M15 website