Secret espionage files concerning World War One have now been made public and are available online.
They include interrogation reports and photographs. The documents include surveillance reports on organisations such as the Bolshevik Party, British Communist Party and The Boy Scout Association.
Among the spies detailed are Swallows and Amazons author Arthur Ransome and Dutch spy Mata Hari, who was executed for spying for the Germans.
Documents reveal details on the British nurse Edith Cavell who saved soldiers in German-occupied Belgium. A prominent memorial to her stands near Trafalgar Square in London.
Less surprisingly, there are details on Russian leaders such as Leon Trotsky and Vladimir Lenin as well as the American expat poet turned fascist, Ezra Pound, who was a major figure in modernist literature.
The publication of more than 150 files is part of the “First World War 100 programme of the National Archives which is commemorating the centenary of the Great War.
A spokesperson said: "Now that we have made the files available online as part of our First World War 100 programme, people across the globe can discover the secret history behind the war for themselves."
