[8] Instead the federation represented and co-ordinated the affairs of the existing local and regional miners' unions whose associations remained largely autonomous.

[8] Within the organisation, each coalfield continued to exercise a degree of autonomy, having its own district association, president, general secretary, and headquarters.

During the first government of Harold Wilson, hundreds of pits closed and thousands of miners left the coal industry but the NUM leadership put up little resistance to the programme.

[15] In the 1980s, because many coal mines were overwhelmingly unprofitable, the Conservative government headed by Margaret Thatcher sought to close them and privatise the rest.

In what the NUM considered a confrontational move, Ian MacGregor, who had overseen cutbacks and closures at British Steel Corporation, was appointed head of the National Coal Board (NCB) by Thatcher in 1983.

Picket lines were stationed outside the pits and other industrial sites requiring coal and violent clashes with police were common.

Although working miners had instigated the legal action, the NUM leadership presented it as an attack on its right to conduct its own internal affairs.

The lack of a ballot reduced public support and made it easier for the government to use legal and police powers against the union without significant political consequences.

After the end of the strike, the NUM took an active leadership role in working to align the labour movement in the UK more closely with LGBT rights issues.

Following the Lesbians and Gays Support the Miners campaign of 1984–85, the organisation's Welsh chapters participated in London's 1985 Lesbian and Gay Pride parade,[19][20] and at the Labour Party's 1985 policy conference, the NUM's unanimous block voting support contributed to the successful passage of Composite 26, a resolution which formally committed the party to an LGBT rights platform.

[25] In 2012 the union's general secretary, Chris Kitchen, admitted it was in decline after the investigative website Exaro[26] revealed that in 2011 the Derbyshire branch had just one member who was not a paid official.