Sir Basil Home Thomson, KCB (21 April 1861 – 26 March 1939) was a British colonial administrator and prison governor, who was head of Metropolitan Police CID during World War I.
This gave him a key role in arresting wartime spies, and he was closely involved in the prosecution of Mata Hari, Sir Roger Casement and many Irish and Indian nationalists.
Thomson ended his university studies after two terms, after suffering bouts of depression, and spent some time from 1881 to 1882 in the United States, working as a farmer in Iowa.
[1] After three years at the Native Lands Office in Suva, Thomson resigned from colonial service, and returned to England in 1893, due in no small part to the deteriorating health of his wife.
In June 1913, Thomson was appointed Assistant Commissioner "C" (Crime) of London's Metropolitan Police, which made him the head of the Criminal Investigation Department (CID) at New Scotland Yard.
As head of CID, Thomson was involved in the arrests in several high-profile espionage cases, including Lieutenant Carl Hans Lody and establishing himself a reputation as a "spycatcher".
[clarification needed] Since the existence of the latter organisation was not acknowledged at the time, Thomson controversially claimed a large proportion of the credit in the successful British counter-espionage operations.
Thomson's efforts were also key in uncovering the first concrete evidence of Turco-German agents operating in the Middle East and attempting to destabilise Afghanistan and British India.
[citation needed] He wrote anti-Semiticly shaded articles for a newspaper, the Whitechapel Gazette, owned by the highly questionable social figure Maundy Gregory.
In December 1925, Thomson was arrested in London's Hyde Park, and charged with "committing an act in violation of public decency" with a young woman, Miss Thelma de Lava.
Thomson rejected the charges, insisting that he was engaged in conversation with the woman for the purposes of research for a book he was writing on London vice; found guilty of public indecency, he was fined £5 (equivalent to £360 in 2023).
When he presented his version in the courtroom he said he was researching a book on the danger of left wing agitators in England and he was together with Miss de Lava waiting for the speech to begin.