Anti-poll tax demonstration, 1990Nearly 30 years ago, anti poll tax demonstrations swept across Britain, culminating in riots in Trafalgar Square in London on 31 March 1990, where more than 100 people, including police officers, were hurt. The tax was seen as deeply unfair a flat rate that penalised the poor and favoured the rich. A few weeks earlier, on 13 March, the Guardian photographer Sean Smith covered a protest outside Islington town hall, one of several local actions that