For other similarly named police units in Commonwealth territories, see Special Branch.
Special Branch was a unit in the Metropolitan Police in London, formed as a counter-terrorism unit in 1883 and merged with another unit to form Counter Terrorism Command (SO15) in 2006. It maintained contact with the Security Service (MI5) and had responsibility for, among other things, personal protection of (non-royal) VIPs and performing the role of examining officer at designated ports and airports, as prescribed by the Terrorism Act 2000.
Harcourt envisioned a permanent unit dedicated to the prevention of politically motivated violence through the use of modern techniques such as undercover infiltration. This pioneering branch was the first to be trained in counter-terrorism techniques.[2] In 1886 its name was changed to Special Branch as its remit had gradually expanded[3][4]
to incorporate a general role in counter-terrorism, combating foreign subversion, and infiltrating organized crime and trade unions,[5][6] becoming the largest Special Branch in the United Kingdom. Although it later became independent of the Criminal Investigation Department (CID), its officers were entitled to use the prefix "Detective" in front of their ranks.
^Wisnicki, Adrian (2013). Conspiracy, Revolution, and Terrorism from Victorian Fiction to the Modern Novel. Literary Criticism and Cultural Theory. Routledge. p. 150. ISBN978-1-135-91526-1. With the collapse of Parnell's political career in 1891 and the general, if temporary, demoralization of the Irish cause, the Special Branch's interests shifted to other revolutionary and anarchist groups, and the word Irish dropped out of the name.