The Chancellor will today outline details of a windfall tax on North Sea oil and gas producers.
The estimated £7billion which will be raised will be used to help consumers, but the levy has not been welcomed by the country's oil and gas industry which is warning of lasting damage to the sector.
The Telegraph reports that every household in the country will get extra money taken off their energy bills this autumn under a new cost-of-living support package - thought to be worth £10billion - to be unveiled by Rishi Sunak.
The Chancellor is to announce an increase to the £200 saving unveiled earlier in the year, and scrap plans to make people pay back the amount over the coming years.
Oil and gas producers will be anxious to learn full details about how the windfall tax will work. All that has emerged so far is that the levy will be linked to how much the firms invest.
"The more you invest, the less you contribute," said one source familiar with the proposal.
But it is thought the tax will not target renewable energy producers, who had warned that doing this would threaten the UK Government's entire energy strategy.
Industry sources say such a move could have destroyed investor confidence ahead of key auctions for licences to develop new wind and solar projects.
Today's announcement in the Commons from the Chancellor is also expected to include details of new "targeted" support for the poorest households, possibly through Universal Credit or extra help for pensioners.
Prime Minister Boris Johnson and Mr Sunak hammered out the agreement after talks earlier this week as they faced growing pressure from voters and Tory MPs to act.
A senior Government source told the Telegraph: "Given exceptional circumstances, we've always said we'd stand ready to provide more support. We will set out more details of those plans on Thursday."
One key area involves the energy bills rebate, which Mr Sunak announced in February in initial moves to help with the cost-of-living crisis.
A £200 discount on energy bills was announced for all UK electricity customers, with the money to be paid back in £40 chunks over five years.
The Treasury has agreed to ditch the loan part of the deal - heavily criticised by Labour - and increase the amount from which each household will benefit.
It means Mr Sunak can declare that around 28million households are getting money off their energy bills, without a need to repay it, from October.
However, the support will still be dwarfed by the jump in energy bills that is coming. The energy price cap will increase to £2,800 according to estimates by Ofgem, the energy regulator. It is around £2,000 currently, and was around £1,300 last October.
Meanwhile, Scottish Government Finance Secretary Kate Forbes has called for a support package of up to £30billion to help households and businesses struggling to cope with the cost-of-living crisis.
Ms Forbes has written to the Chancellor asking for a variety of measures, including an emergency cost-of-living cash payment of up to £1,000 to all UK households with below-median income.
She has also requested that the windfall tax is applied to all firms who have benefiting from significantly-higher profits over the pandemic and energy crisis.
Ms Forbes goes on: "Oil and gas companies, who are disproportionately based in Scotland, are not the only businesses that have profited during the pandemic and current crisis. Any one-off windfall tax should be applied to all companies unfairly benefiting from significantly higher profits, to ensure that Scottish industry does not carry a disproportionate burden of funding a UK-wide response."