Boris Johnson looks set to press ahead with a manifesto-busting National Insurance hike despite a warning that Tory votes will "evaporate".
Tory former Cabinet Minister David Davis urged Mr Johnson to scrap the 1.25 percentage point increase to National Insurance in April, which will heap misery on families facing a growing cost of living crisis.
Opposition is mounting among top Tories to tax hikes to fund health and social care - with one minister claiming the entire cabinet opposed the idea.
Commons Leader Jacob Rees-Mogg is said to have called for the move to be abandoned, while former Brexit Minister Lord Frost blasted the idea when he quit his role last year.
The manifesto-breaking tax rise was confirmed last September to tackle Covid backlogs in the NHS and to fund social care.
Mr Davis told the BBC : "At the last election, one of the things that came up on every doorstep I went to in all the swing, all the Northern seats around me, was - ' Jeremy Corbyn going to put taxes up, therefore, I'm going to vote for you'.
"And what are we going to do? Put taxes up. What do you think's going to happen? Those votes, they're going to evaporate.
"So for our own political interest, but more importantly for the national interest - we should keep taxes down."
Mr Davis, a former Brexit Secretary, last week called on Mr Johnson to quit following the row over Downing Street parties.
He argued the NI hike was "economically unwise" because it created a "disincentive to work", would "penalise employers" and "hit the growth of the whole economy".
One minister told the Mail there would be "no objection" from the Cabinet if the increase was scrapped.
The minister said: "If the Chancellor proposed to the Cabinet that he wanted to cancel the national insurance contributions rise, there would be no objection to it.
"There would be no objection from the Prime Minister either because this is very much a Treasury policy."
But Mr Johnson looked set to press ahead with his plans.
Speaking on a visit to Milton Keynes Hospital, he said: "The NHS has done an amazing job but it has been under terrible strain.
"Listen to what I'm saying: We've got to put that money in. We've got to make that investment in our NHS.
"What I'm telling people is, if you want to fund our fantastic NHS, we have to pay for it - and this Government is determined to do so."
Downing Street defended the move, saying it was the "right approach to tackle this long-standing problem".
Education Secretary Nadhim Zahawi said it was vital to fix social care - and the tax hike was the "right thing to do".
"It is really important to remember that the highest earners, the 14% who earn the most are paying 50% - they are paying half of that contribution, and the lowest earners, 6.1 million of the lowest earners pay nothing, so it is as progressive as we can make it to deal with a problem that breaks many an individual in their old age.
"So it is really important to just focus on why we are doing this, why I think it is the right thing to do, because it will finally create a system of adult social care that is sustainable and deliverable without breaking families."
