Sir Keir Starmer’s successor must immediately slash energy bills, the SNP has said.
The party made the call as consumers face a 13% rise in energy bills from the start of July – with the average yearly bill climbing to £1,862.
SNP Westminster Dave Doogan warned Labour against failing to keep its manifesto pledge to reduce energy bills by £300 by 2030.
Following the Prime Minister’s resignation, and the strong possibility that he will be replaced by Andy Burnham, research from the House of Commons Library on energy prices, commissioned by the SNP, has been published.
It shows the looming price rise will be the sixth increase in energy bills since Labour returned to Government in 2024, increasing by £294 in that time.
The SNP said the analysis showed energy had “soared” under successive UK governments.
According to the Commons Library, households at the turn of the century spent an average of £11.44 a week on electricity at today’s prices.
At the most recent count, weekly spending on electricity had risen to £21.79 per week. Weekly spending on gas has risen from £11.39 to £20.59.
For households reliant on heating oil – about 142,000 in Scotland – the cost of energy has risen even higher.
In 1999, the typical UK mid-month price for heating oil was 25.1 pence per litre in today’s prices.
By July 2024, that had risen to 62.8 pence per litre and, by May 2026, it had risen to 89.7 pence per litre – a real terms increase of 56% since 2024 and 357% since 1999.
The SNP said the UK Government’s tax and energy policies were having an impact on prices.
It said the 5% VAT placed on energy adds £86 per year on average, while policies on standing charges have also seen costs grow in recent years.
Mr Doogan said: “The next UK prime minister must immediately slash the cost of energy bills to avoid damaging their reputation by repeating another broken Labour Party election promise.
“From next week, energy bills will increase to almost £600 more than the Labour Party promised at the election – leaving millions of households paying through the nose in rip-off Britain.
“The betrayal on energy bills is one of the biggest symbols of the litany of broken promises by the Labour Government – and reversing it is essential for any Prime Minister who wants to avoid the same fate as Keir Starmer. It will be one of the first big tests of the next prime minister.
“While many parts of Scotland and the UK are currently enjoying sunny weather, the soaring cost of electricity will still hit families hard when it comes to powering our homes and the energy-intensive appliances households use on a daily basis, including showers, washing machines, fridge freezers, TVs, cookers, and air fans.”
Mr Doogan said Scots would be hit hardest by energy costs with families north of the Border “forced to pay some of the highest standing charges anywhere in Broken Brexit Britain”.
He added: “It is a scandal that families in energy-rich Scotland are being forced to pay sky-high energy bills by the Labour government. Westminster has taken over £400 billion of Scotland’s energy wealth and, instead of investing it in Scotland, they have closed down Grangemouth and are destroying thousands of vital Scottish energy jobs in the North Sea.
“It shows why it is vital that Scotland secures a fresh start with independence so we can use our huge energy wealth to lower bills, create jobs and invest in our communities.”
A spokesperson for the Department for Energy Security and Net Zero said: “Tackling the affordability crisis is the Government’s number one priority.
“We have taken £150 of costs off energy bills for the years ahead and extended the warm home discount to around six million households.
“We are also accelerating home upgrades that will cut bills and shield families from fossil fuel shocks – including bringing plug-in solar to the UK.”