UK Special Branch
though be advised that the official narrative is particularly suspect.
Special Branch is the name of units responsible for matters of national security in British and Commonwealth police forces, as well as in Ireland's Garda Síochána. The remit of Special Branch is to acquire and develop intelligence, usually of a political nature, and to conduct investigations into perceived threats of subversion against the State.
The first Special Branch, or Special Irish Branch, as it was known, was a unit of London's Metropolitan Police formed in March 1883 to combat the Irish Republican Brotherhood. The Irish soubriquet was subsequently dropped as the unit's remit widened. During the same period it became active in the policing of so-called 'Anarchist' groups, mainly expatriats from Continental Europe, especially the French Communards and Russian Tsarist dissidents. One of its more infamous episodes was facilitating and organising what became know as "The Walsall Bomb Plot" of 1890 in which 3 hot-head dissidents were enveagled into constructing primitive bombs from equipment and know-how provided by Special Branch agents, then caught 'in the nick of time' and sentenced to 20 years in prison. The episode elevated Special Branch Inspector William Melville (ironically an Irishman) to heroic status. He went on to take over from Chief Inspector Littlechild as head of Special Branch and later to oversee the formation of MI5 - a sort of latter day Robert Cecil (of Gunpowder Plot fame) you might say.
Since that time, where matters of Deep State policy are concerned, police/security service methods have clearly changed only in their scale, sophistication and ambition as ever greater resources have been allocated to them.
The Wikipedia article on the Walsall Bomb Plot referenced below is a good introduction to the subject