The economist behind Labour's promise to cut Brits' energy bills by £300 has admitted the claimed savings could be 'wiped out' by rising electricity costs.

Pawel Czyzak, who penned a 2023 report for energy think tank Ember, said the UK now faced 'a much different situation' to when he wrote the research.

Prior to last year's general election, Labour promised its planned move to 'clean power' by 2030 would slash £300 off the average annual household energy bill.

The party cited Mr Czyzak's analysis as the basis for its pledge to deliver savings for families through decarbonising the electricity grid.

Energy Secretary Ed Miliband on Sunday stood by the promise to cut bills by up to £300 by the end of the decade as he defended his Net Zero agenda.

But, speaking to the BBC, Mr Czyzak has cast doubt on whether the savings can be delivered.

Asked if the £300 savings estimate still stood, the energy expert said it was now 'a much different situation than it was in 2023'.

Mr Czyzak said the savings he projected were dependent on a significant drop in wholesale electricity costs as renewables become cheaper and the main source of power in the UK.

Energy Secretary Ed Miliband recently stood by the promise to cut bills by up to £300 by the end of the decade as he defended his Net Zero agenda

'I think the question now will be whether the high cost of offshore wind doesn't disrupt some of these wholesale energy savings,' Mr Czyzak said.

He added, if the cost of upgrading the electricity grid increased, and wholesale prices don't go down as much, 'then it's going to be hard to generate savings'.

'So then, yes, there is a risk of these savings being wiped out if we can't get the actual electricity cost down, and that might happen if offshore wind is too expensive,' he continued.

Mr Czyzak said Ember never suggested the £300 pledge was 'the best solution to everything'.

'I think it's generally quite a tricky one because of the volatility around everything. Everything in this market is very volatile,' he continued.

'So if you're just looking for a fixed single number, it's not that easy to deliver.'

But he added that Labour's pledge could still be achieved in a number of ways - including by removing costs such as green levies from energy bills, or financing grid investments through rises in other taxes.

In its 2023 analysis, Ember said UK households 'could save £300 every year on their electricity bills in 2030 if the government completes its switch to a mostly clean power system by then'.

The report added that 'savings from low-cost renewables far outweigh the total investment costs required'.

Ember said its baseline for measuring these savings was Ofgem's energy price cap between July and September in 2023.

At the beginning of this month, the energy regulator increased its price cap again.

It meant the energy bill for the average household paying by direct debit for gas and electricity increased from £1,720 to £1,755 per year.

During a TV interview on Sunday, Mr Miliband insisted that bills currently remained 'too high' because of 'our dependence on fossil fuels'.

'There is only one route to get bills down, which is to go for clean power, home-grown clean energy that we control so we're not at the behest of the petro states and the dictators,' he added.

Both the Conservatives and Reform UK have vowed to ditch Britain's commitment to reach Net Zero by 2050 in a bid to reduce electricity costs.

And US President Donald Trump has told Sir Keir Starmer to ramp up the production of fossil fuels to cut energy bills as he urged the Prime Minister to 'drill, baby, drill'.

A spokesperson for Mr Miliband's Department for Energy Security and Net Zero said: 'We remain determined to bring down bills, for good, and stand by our commitments.

'It is central to every decision we make and why we have already consented a record amount of clean energy - enough to power the equivalent of over 7.5 million homes and reach our offshore wind target.

'The main reason energy bills remain high is because wholesale gas costs for households remain 75 per cent higher than they were during the year before Russia invaded Ukraine in 2022.

'By making Britain a clean energy superpower we are getting the UK off the rollercoaster of fossil fuel prices and onto clean, homegrown power that we control.'

Fresh doubt over Labour's promise to cut Brits' energy bills by £300