Alex Eadie

Alex Eadie, who has died aged 91, was for 32 years a miner and miners' agent who went, as he said himself, "from the coalface to the House". An MP for 26 years, he championed the coal industry during a long period of decline from the late 1960s until the miners' strike of the Margaret Thatcher era.

Elected to represent the mining constituency of Midlothian in 1966, he used his maiden speech to warn that the British mining industry was being run down "at a very dangerous pace" that would "do the economy of the country substantial harm". Talking as a miner, he argued that the UK could not hope to prosper as an industrial country without its own indigenous resources of energy.

Born in Buckhaven, Fife, his father, also a miner, died in a pit accident as he neared retirement. Alex Eadie left school at 14 to work in the pit, although he also studied mining engineering part-time. He worked at Lochhead Colliery until 1965, at which point he became the miners' agent for Clackmannan.

Active in the National Union of Mineworkers (NUM) from his teens, he also joined the Labour Party in 1943 and, two years later became Scottish president of the Young Co-Operators. As a member of Fife County Council, he served on its housing and education committees for more than a decade.

He first contested Ayr at the General Election of 1959, and again in 1964 (when he was defeated by the future Tory minister George Younger). He had slightly better luck in trade union politics, coming within 3000 votes of beating Alex Moffat to the presidency of the Scottish NUM in 1961. Within a year of entering the Commons, he was appointed Parliamentary Private Secretary to the pensions minister Margaret Herbison, but stayed in post for only four months before being sacked by Harold Wilson for refusing to support his application to join the Common Market. He was also hostile to the then-emerging SNP, co-authoring a critical pamphlet (memorably entitled Don't Butcher Scotland's Future) with fellow Labour MP Jim Sillars.

"The Scottish people do not deserve to be led blindly up the path of separation," they argued . "It is our job to open their eyes to the facts; it is our duty to ensure that the logical repercussions of separation are made widely known." Like Mr Sillars, Mr Eadie later softened his stance, and became a key figure in converting Scottish colleagues to the constitutional compromise of devolution. On other issues, including David Steel's Private Member's Bill to liberalise abortion laws, he was similarly pragmatic.

It was in the turbulent 1970s, however, that his career really took off. A leading critic of Edward Heath's Industrial Relations Bill, he was also prominent during the 1972 coal strike, telling Employment Secretary Robert Carr that his Government would "never break the miners' spirit". The following year, Mr Wilson appointed him opposition front bench spokesman on energy, including North Sea oil.

From February 1974 he became an under secretary at the Department of Energy (DoE), serving, at first, Eric Varley, and then Tony Benn, who valued his junior minister's direct knowledge of the mining industry. As well as working hard to restore moral among coal workers, he promoted research into what became known as "alternative" energy while overcoming earlier opposition to nuclear power.

An example of his integrity came in 1977 when he warned Mr Benn that he could not support direct elections to the European Parliament because his constituents would feel betrayed. "I can't twist and turn and lie and cheat in order to remain in office," he explained. "Anyway I have got my Coal Bill through and therefore in a way I feel I have done my work as a minister." Mr Benn agreed, and noted in his diary that he "admired Alex for saying that".

Nevertheless, he remained at the DoE until 1979, and thereafter shadowed the energy brief from Labour's front bench. During the divisive miners' strike of 1984-85 he was prominent as Neil Kinnock's spokesman on coal and, although he was no fan of Arthur Scargill, supported the strike while urging Thatcher's Government to show "conciliation, not confrontation".

Mr Sillars, who was Mr Eadie's election agent in 1964, said he had "tremendous strength of character, enormous courage and rock-hard principles". "Alex also had a workrate matched only by Tam Dalyell in the House of Commons. He was a wholly admirable person; he enjoyed respect from all quarters of the Commons and was knowledgeable, although never arrogant, about his subject."

He retired from the House of Commons in 1992. A teetotaller who campaigned against smoking, he was typical of a generation of working-class men who embraced education in order to escape the mines.

In retirement he indulged his hobbies of gardening and bowling, but even into his 90s remained a passionate political debater and supporter of his local East Fife football team.

Mr Eadie died on 26 January. His first wife Jemima Ritchie died in 1981, and in 1983 he married Janice Murdoch.

She and a son, whose wife, Helen Eadie, is a Labour member of the Scottish Parliament, survive him.