Peter Heathfield

As general secretary of the National Union of Mineworkers, Heathfield was one of the triumvirate of men who led the union into the strike, along with president Scargill and vice-president Mick McGahey.

Although those who knew him believed that Heathfield had grave doubts about Scargill's strategy, in leading a strike against pit closures in March 1984 without a coalfield ballot, the general secretary never gave public voice to these opinions. Had he done so, the course of the strike, and the future role of coal in Britain's energy policy, may have turned out very differently. Yet Heathfield valued his loyalty to Scargill, and to the striking miners, too highly to open a damaging split in the NUM hierarchy.

When the miners returned to work in March 1985, having failed to reach any agreement with the National Coal Board, Heathfield was plunged into despair, a condition from which he never recovered and which was exacerbated by unproven media allegations of financial impropriety.

Like Scargill, he chose to keep his own counsel in the years following the strike, but in a rare interview in October 1990 he admitted: "I never imagined I would have to face the kind of pressure that I experienced during the year-long strike, but the animosity and vilification that has emerged in large sections of the media during the past four months has been pretty overpowering."

Heathfield was born in Somercotes, near Alfreton, Derbyshire, the son of a railway signalman whose work took him to Chesterfield where Heathfield went to school before getting a job in a colliery drawing office and then working underground at Williamthorpe colliery.

Identified by the local NUM leader, Bert Wynn, as a highly intelligent young man, Heathfield was encouraged to take extramural courses at Sheffield University in the company of future Labour MPs Eric Varley and Dennis Skinner. He also became active in the party and was elected as a councillor in Chesterfield before failing to win the Labour parliamentary candidacy for Ilkeston in 1963.

It was at this time that he met and married Betty Vardy, a former member of the Communist Party, who went on to chair the group Women Against Pit Closures, leading the campaign – along with Scargill's wife, Anne – to give practical support to miners and their families during the strike.

His parliamentary ambitions put to one side, Heathfield made rapid progress in the union, becoming a full-time official in 1966, vice-president of Derbyshire NUM in 1970 and Derbyshire area secretary in 1973.

When Scargill stood for the NUM presidency in 1981, Heathfield stood aside to give his friend, and junior by nine years, a clearer run. Heathfield then became general secretary on March 1 1984, five days before the strike began. Seen as a pragmatist who might provide a balance to the hot-headed Scargill, Heathfield declared: "I am not going to be anybody's lapdog." On the same day, Tony Benn, a man whom Heathfield admired immensely, won a by-election in Chesterfield, largely owing to Heathfield's local power-base.

After the strike, however, Heathfield, like the NUM, was a shadow of his former self, taking early retirement from his post in 1992. His marriage broke up and he suffered health problems, exacerbated by the sensational claims that he and Scargill had mishandled union funds.

These allegations grew ever more lurid, including claims that Scargill had asked Libyan dictator Muammar Gadaffi for cash and weapons, but both Heathfield and Scargill were cleared by an independent inquiry chaired by Gavin Lightman QC.

Roy Greenslade, the editor of the Daily Mirror at the time the claims were first published, later apologised to both men and reports have since suggested that MI5 was behind a plot to discredit the NUM leadership.

Paying tribute to Heathfield this week, Scargill said: "The miners have lost an outstanding champion, a courageous fighter, and I have lost a dear, close, personal friend."

TUC general secretary Brendan Barber said: "Peter Heathfield was a thoroughly decent, principled trade unionist whose passing will be widely mourned. Along with Arthur Scargill and Mick McGahey, he led the miners with courage and determination during the bitter dispute of 1984-85."

Peter Heathfield is survived by his second wife, Sue, and his three sons and daughter by his former wife, Betty, who died in 2006.