UK energy bills would be frozen until 2024, when the next general election is expected, under plans being considered by Liz Truss.
The Foreign Secretary will become Prime Minister today, replacing Boris Johnson, after winning the Tory leadership race.
Following a visit to Balmoral to be appointed by the Queen, Ms Truss will outline her vision for her premiership and set out a policy drive for her first 100 days.
A package of energy-bills support for households is due to be revealed as early as Thursday, followed within weeks by a formal announcement of tax cuts.
The Telegraph understands that, among the moves to tackle the cost of living crisis, Ms Truss could freeze energy bills for all households until 2024.
The "huge" policy intervention would last longer and cost tens of billions of pounds more than the Labour Party's proposal to cap prices at their current levels until early 2023.
Cabinet appointments will be announced tonight, with half a dozen of Ms Truss's most loyal supporters, largely on the party's Right, to be given the most senior roles.
Twin package of measures
Ms Truss's first policy announcement will be what campaign figures have called a twin package of measures to provide help to households with soaring energy bills, plus reform of energy supply.
While the Truss campaign continued to stay silent in public about the measures on Monday, details of options being considered were emerging.
The Telegraph understands that Ms Truss plans to institute an energy bill freeze that could last all the way to 2024 and is also leaning towards applying the freeze to all 28million households rather than offering means tested support.
One government figure familiar with Truss campaign policy discussions said the intervention would be "huge" and that the campaign wanted a "simple" solution.
Kwasi Kwarteng, set to be appointed chancellor, hinted at a two-year intervention in the Financial Times, saying the package would help businesses and families "through this winter and the next".
Freezing the price cap would mean annual energy bills for the average household would remain at £1,971 instead of jumping to £3,549 next month. The overall package could cost the Treasury up to £100billion.
The money could be provided to energy companies as a loan, and industry bosses are understood to have suggested that this be repaid via a levy on household bills after the crisis has passed. However, this would mean that household bills would not fall as quickly as otherwise.
Loans could be repaid over many years
The loans could be repaid from bills over the next 10-20 years.
The energy plan will also include help for businesses. Campaign figures have said the problem is much more complicated than that with households because the price cap does not apply to companies.
The second section of Ms Truss's energy package will focus on increasing supply in the medium term. The moratorium on fracking is expected to be lifted with the change coming into place within weeks, opening the door to drilling for shale gas south of the border if it is supported by local communities.
Removing regulations limiting offshore wind farm construction and North Sea oil drilling are also being worked on.