In 1971, he was elected as leader of the NUM and presided over the national strike that began on 9 January 1972. The strike lasted for seven weeks and the Middle East oil crisis caused widespread power cuts. Emergency measures were used to economise on electricity by reducing the working week to three days. After much negotiation the strike was resolved on 25 February 1972 with a 21% increase in pay and concessions won by the miners. Miners moved to the top of the UK's industrial wage league, having previously been seventeenth. Only two years later, NUM members voted again to strike and stopped work on 4 February 1974. Prime Minister Edward Heath called a snap election on this issue, asking the public, "Who governs Britain?" Gormley tried to persuade the National Executive Conference to postpone the strike until after any election, but the strike went ahead. After the election brought in a new Labour government, the union's demands were met.
1980s
In 1981, Prime Minister Margaret Thatcher threatened to break with the 'Plan for Coal' and close 23 pits. A ballot for strike was held if the government closed pits contrary to the Plan for Coal. A strike mandate resulted with an 87.6% majority. The NUM Executive had a clear mandate for strike action if the government breached the Plan for Coal agreement. When a national strike was threatened, Thatcher backed down; many miners went on unofficial strike in the year, but Gormley rejected calls for a national strike. He left his post in 1982 and was replaced by the more left-wing Arthur Scargill. In 1982, his last-minute appeal got miners to accept a Government offer of a 9.3% raise, rejecting Scargill's call for a strike authorisation. When asked what he had achieved during his period as President, he replied, "Everyone wants to be related to a miner". One of Gormley's long-term legacies which affected the 1984–85 strike was his role in the wage reforms of 1977. The reforms paid miners a wage proportionate to the output of their region. This gave Nottinghamshire miners the highest wages of all and so they were very reluctant to go on strike in 1984, when few of their pits were under threat and those miners had high wages to lose. Another key matter was that two ballots of the NUM membership had rejected these reforms, and Gormley responded by declaring productivity schemes now to be for the regional committees to decide, with or without a regional ballot. When this was challenged in the High Court as a violation of union rules, the court upheld Gormley. This confusion over when the NUM needed to hold a ballot became of huge importance during the 1984-85 strike, when Scargill tried to mimic Gormley's methods and make a national strike into something on which regional committees could decide. He was made a life peer as Baron Gormley, of Ashton-in-Makerfield in Greater Manchester in the 1982 Birthday Honours. He was the subject of This Is Your Life in 1982 when he was surprised by Eamonn Andrews.
In 2002, the BBC uncovered that Gormley had worked for Special Branch by passing on information on extremism within his own union. A former Special Branch officer made this allegation and said that Gormley "loved his country. He was a patriot and he was very wary and worried about the growth of militancy within his own union". The BBC claimed, "Special Branch was talking to more than 20 senior trades union leaders during the early 1970s".
