Chris Marshall met the girl he was going to kill on a warm night in early June, when one of the colleges in Oxford was holding its summer ball. The undergraduates were having their final fling before leaving to become merchant bankers or diplomats or advertising agents. They paid a great deal of money for tickets to balls like this – a hundred pounds, or even more in some cases. For that they expected a great deal in return, and the organizing committees worked hard to provide it: marquees with dance floors, champagne buffets, hot new bands and famous old ones, alternative cabarets – whatever entertainment was fashionable, expensive, and available.

   This particular college had grounds that bordered a lake. There were going to be fireworks, there was a 1920s-style dance band on a floating platform, there was a cabaret-circus in a marquee; it was altogether a spectacular event, one which the undergraduates felt embodied the wealth and splendour due to them, at this time, in this country.

   Chris Marshall wasn’t an undergraduate. He was seventeen, with a year still to go at school, and this was a holiday job of sorts, though the holiday was some way off yet. He worked part-time for a firm called Oxford Entertainment Systems, owned by a man named Barry Miller. Barry knew that Chris was saving for a decent bike, so he offered him twenty-five pounds for the night’s work, even though he didn’t really need help. Chris was glad to do it. He was tired of sitting at home with his mother and her new lover, trying to make conversation and feeling himself in the way all the time. He’d never felt like that at home before, and it was uncomfortable.

   So on a warm evening in June, Chris found himself setting up the lights for the cabaret-circus.