Douglas Peroni was an active member of the British Union of Fascists from the middle of the 1930s until the early 1950s. During the 1930s, Peroni was treasurer of the Hampstead branch of the BUF, and during World War II, he was detained, along with many other supporters of Mosley, in Brixton and the Isle of Man under Defence Regulation 18B.

After the war, like many of Mosley´s supporters, he remained active, and ran the Hampstead Literary Society, intended as the nucleus of a future party branch. At that time, Peroni was working as an accounts supervisor with a firm of London bookmakers. In February 1948, Mosley announced the formation of the Union Movement, and the Hampstead Literary Society reconstituted itself as the Hampstead branch of the UM, meetings of which were regularly disrupted by members of anti-fascist groups.

Peroni stood in several local council elections in Hampstead (London), but generally support for fascism was negligible (in 1949, Peroni stood in Hampstead´s town ward and polled a derisory 81 votes out of the 24,799 cast). Peroni stated that the Hampstead branch was "going ahead by leaps and bounds" and claimed "the record for street sales" of the Union, but his wife´s opinion was that he had to go out "selling papers in person five nights a week otherwise the others don´t turn out".

In the 1950s, it became apparent that the UM was a spent force, particularly when Mosley moved to Ireland in 1951. After further poor showings at elections, Peroni resigned, and the local UM branch closed.

Douglas Peroni died in 1987.