Conservative right-wing leader Margaret Thatcher sought to make the British coal industry more efficient. In March 1984, Thatcher and the National Coal Board announced 20 mines would close, erasing 20,000 jobs.
Days after the announcement, 165,000 miners, led by the National Union of Mineworkers, went on strike. Thus began a tense, year-long strike, where men would throw pickets — known as "flying pickets" — at pits where miners still worked at.
The strike grew violent during a confrontation at a coking plant in June 1984, when police and strikers through bricks and fought each other. In December, two strikers killed a taxi driver by hitting him with a concrete block intended for a working miner.
The strike eventually ended in March 1985, and is considered a victory for Thatcher and her Conservative Party. The event also shrunk the NUM's influence in politics, according to PBS.
Source: National Coal Mining Museum for England, BBC, PBS