Thom Ryder: Avenging Angel (UK 1975)
From the Publisher:
The rebellious freedom-loving spirit of the Angels still lingered on here and there, despite the efforts of the forces of law and order. And there was another threat too, posed by the short-haired, fashionably dressed groups of sixth formers known as the Dudes, who were becoming unbelievably vicious and cruel.
And then, one night, a group of leather jacketed youths swooped on a Dude Club. They rode in full glory on their hogs, and the days of gang warfare were returned, only more bloody. A wave of violence sweeps the country and the vengeance of the Angels is complete.
Thom Ryder: Avenging Angel. New English Library, ISBN: 0450022005 (March, 1975), 125 p., £0.35.