LIZ Truss plans to cut the basic income tax rate from 20p to 19p to put money back in the pockets of Britons.
The Prime Minister is aiming to bring forward the move, which was scheduled for 2024, as she kicks off her post as Prime Minister in earnest.
This decision would be announced by Chancellor Kwasi Kwarteng during the mini-budget on Friday, but it is not known from when it would apply.
It will also cancel the 1.25% hike in National Insurance which is due to come into effect from November.
Mr Kwarteng, who also plans to lift the cap on bankers’ bonuses to boost the City of London, may have to circumvent budget rules that commit ministers to debt reduction.
But a source said the prime minister’s quest for growth would trigger a “seismic shift” in politics.
Senior Tory MP Sir Iain Duncan Smith said: ‘Liz Truss was elected on a platform of tax cuts, making it clear that you cannot tax your way to growth.
“We are heading into a very tough winter and now is the time, I think, that she will be bold.”
Business Secretary Jacob Rees-Mogg, meanwhile, will announce help for businesses facing high energy bills.
Health Secretary Therese Coffey is set to revise A&E targets to reduce waiting times.