It was summer 1981, and the towns and cities of Britain were alight. There had been riots in Brixton, south London, that April and on 10 July there were more — and not just in Brixton. Other parts of the city followed. And so did a long list of other places, from the unsurprising — Sheffield, Preston, Leicester — to the ones where the idea of a riot might have been expected to have disappeared with Captain Swing: Cirencester, Aldershot.