Impartiality Against the Mob — John Creasey

A secret fascist organisation intends to attack a dock-gate meeting of workers and Commander Gideon of Scotland Yard has the job of ensuring the police both maintain law and order and maintain impartiality, not provoking either side. At the same time, brutal murder is occurring behind an anti-immigration campaign. Gideon finds himself risking his life so as to protect the force and its reputation, when everything seems ranged against it. And, of course, ordinary day to day policing must continue.