From Longman Dictionary of Contemporary EnglishSpecial BranchˈSpecial ˌBranch noun SCPSPYa department of the British police force that deals with political crimes or crimes affecting the safety of the government, for example terrorism
Examples from the Corpus
Special Branch• When I asked Special Branch for extra men for surveillance work, I was told there were no extra men available.• Not necessarily for us yet, but we've been asked by Special Branch to take it on board.• Harris, Harvey - some such name. Special Branch ... Two men in boiler suits emerged from inside the rear van.• He has been protected by a team of Special Branch officers, moving him from location to location.• The Special Branch man couldn't believe his eyes as all our clobber went into the plane at Elstree.• The security forces have deployed more undercover Special Branch and Military Intelligence staff in notorious paramilitary stomping grounds.• The one who got shot in the chest when Special Branch and MIs tried to pick him up in Bayswater. 