CaptionA member of the riot police leads a demonstrator away from a burning Trafalgar Square. A rally against the Poll Tax, introduced by Margaret Thatcher's Conservative government, developed into what were arguably the worst riots in the centre of London for a century. What began peacefully, soon escalated into a violent confrontation between riot police and demonstrators who used all they could lay their hands on, but to no avail - the community tax remained in force. The battle lasted several hours with casualties on both sides.