The Poll Tax was a new local tax introduced by the Conservative government in 1989. It was a fixed charge that all taxpayers had to pay, regardless of their income. This meant that poorer people paid a much higher percentage of their income than the better off.
A movement grew to resist the Poll Tax by refusing to pay it. This movement organised itself into local Anti Poll Tax Unions, or APTUs. The APTUs organised mass meetings, physical resistance to bailiffs trying to collect the tax, and protests at and occupations of town halls and council buildings.
The Poll Tax was eventually defeated by widespread self-organisation and direct action. The APTUs allowed people to meet and make their own decisions, and the non-payment campaign created a direct confrontation with the state.