The union said Housing Minister Kevin Stewart’s plans to spend an additional £10 million on warmer homes were undermined by “massive” price rises from the big energy companies.

Mr Stewart yesterday opened the national Fuel Poverty Matters conference in Clydebank.

Unite Scottish secretary Pat Rafferty said: “Successive Scottish Governments have spent hundreds of millions of pounds on making homes warmer - but rising energy costs wipe out the gains and keep people in fuel poverty.

“Until we regain public control and ownership of energy, the private companies will carry on putting profits above people’s lives.

“Surveys have shown that a large majority of people support public ownership of energy utilities and it’s time politicians followed their lead. We welcomed Jeremy Corbyn’s call to bring the Big Six energy firms into public ownership. It’s time that other political leaders took the same position.

“Public ownership of energy might not happen overnight, but it won’t happen at all if politicians don’t take a stand for it. Unite urges them to do so – because this is literally a matter of life and death for many people in Scotland.”

Unite said research had showed a move to a publicly-owned energy system in the UK would pay for itself within 10 years, and could save households around £158 a year on their bills.