Before it erupts into a full-scale riot, peaceful protesters against Margaret Thatchers Poll Tax policy, gather in Whitehall, on 31st March 1990, in London, England. London, England. Later that day, angry crowds stormed the Whitehall area and then Londons West End, setting fire to a construction site and cars, looting stores up Charing Cross Road and St Martins Lane. The anti-poll tax rally in central London erupted into the worst riots seen in the city for a century. Forty-five police officers were among the 113 people injured as well as 20 police horses. 340 people were arrested.