Boris Johnson has been urged to apologise for "offensive" comments about Margaret Thatcher helping the environment by closing coal mines.
The PM said the closures gave the UK "a big early start" in the fight against climate change.
He was speaking on a visit to an offshore wind farm in the Moray Firth.
Scotland's First Minister Nicola Sturgeon said the remarks were "crass and deeply insensitive" to mining communities.
She tweeted: "Lives and communities in Scotland were utterly devastated by Thatcher's destruction of the coal industry (which had zero to do with any concern she had for the planet)."
Labour said he should apologise for the "shameful" comments.
The party's Welsh First Minister Mark Drakeford told BBC Radio 4's Today programme: "The damage done to Welsh coal mining areas 30 years ago was incalculable and here we are 30 years later the Tories are still celebrating what they did."
On Thursday, during a two-day visit to Scotland, Mr Johnson was quizzed about preparations for the COP26 climate summit in Glasgow in November.
Pushed on whether he would set a deadline for ending the extraction of fossil fuels, he said the UK had already transitioned away from coal in his lifetime, and he suggested Mrs Thatcher had inadvertently got the ball rolling.
He said: "Thanks to Margaret Thatcher, who closed so many coal mines across the country, we had a big early start and we're now moving rapidly away from coal altogether."
He is reported to have laughed and told reporters: "I thought that would get you going."
Boris Johnson may be ill-advised to summon the ghost of Lady T to support his climate policies - but he has a point.
In 1989, the Iron Lady riveted the United Nations by warning that greenhouse gases were "changing the environment of our planet in damaging and dangerous ways".
She continued: "The result is that change in future is likely to be more fundamental and more widespread than anything we have known hitherto."
Her pit closures were not part of a green policy, but they did fortuitously show the UK could prosper without coal.
This made Britain a global leader on climate change. But it crushed communities.
Politicians don't want to repeat the mistake, so they aim to create jobs in the environment sector.
But so far, the PM's climate advisors say his policies on green jobs are running behind his rhetoric.
Mr Johnson said there was a "massive opportunity" to increase the use of more environmentally friendly technologies.
But he also stressed that there needed to be a "smooth and sensible" transition from oil and gas to greener forms of power.
In 1984, there were 170 working collieries in Britain, employing more than 190,000 people - but by 2015, they had all closed.
Mrs Thatcher's announcement that she planned to close 20 of them, led to the year-long miners' dispute.
Millions of people protested against pit closures and throughout the summer of 1984 there were violent clashes between striking miners and police, whose numbers often ran into several hundred at each confrontation.
Violence led to widespread use of the breach of the peace charge.
In October, it was announced that miners convicted during the strike would be pardoned by the Scottish government following an independent review.
Responding to Mr Johnson's comments, SNP Westminster leader, Ian Blackford, tweeted that Mrs Thatcher had "devastated communities across Scotland".
He wrote: "Many still bear the scars of brutal Tory cuts."
BBC Political Correspondent, Nick Eardley, tweeted on Thursday that "a few Scottish Tories have their head in their hands tonight after what they thought had been a decent first trip to Scotland since January".
He added they had described the comments as an "unforced error", "not helpful" and "crass".
Labour is opposed to the opening of new coal mines, saying they are not compatible with the UK wanting to be a world leader in reducing carbon emissions.
But Labour leader, Sir Keir Starmer, tweeted that Mr Johnson's comments were "shameful".
He wrote: "Brushing off the devastating impact on those communities with a laugh, shows just how out of touch he is with working people".
And in a statement, shadow foreign secretary, Lisa Nandy, said the prime minister should apologise.
She said the remarks "reveal the Conservative party's utter disregard for the communities still scarred by Thatcher's closure of the mines and failure to deliver good jobs in their place".
"It is vital that a green transition is a fair transition" she added.