Most Brits oppose "morally indefensible" government plans to slash benefits in real terms, new research shows.
Liz Truss is accused of being "completely out of touch with public opinion" as she weighs up increasing payments by 5.4% instead.
Her predecessor, Boris Johnson, had pledged benefits would rise with inflation - which currently stands at 9.9% - and campaigners warn a U-turn will push the poorest people into the country into misery.
Ms Truss has refused to commit to keeping the government promise, sparking huge divisions within her own party, while former PM Gordon warned of a "national uprising".
A study released today by charity The Joseph Rowntree Foundation (JRF) and YouGov found that 61% of voters agrees that benefits should rise with inflation.
Nearly half of those who voted Tory in 2016 believe benefits should rise with inflation, with 49% who backed Mr Johnson supporting the move.
Just one in five - around 19% - say there should be a below-inflation rise, while a cruel 7% say the rates shouldn't rise at all.
Analysis by JRF found that a couple on benefits with two children would lose £300 a year if the government opts to increase benefits in line with earnings, currently 5.4%.
The poll of nearly 1,700 people was carried out during the Conservative Party Conference, as splits emerged within the party over the issue.
It comes hot on the heels of a separate survey by Survation for campaign group 38 Degrees, which found only 19% of Brits believe the Prime Minister’s mini-Budget should be implemented.
Ms Truss's lurch to the right has raised fears within the party that Tories could be set for annihilation at the next General Election.
Analysis found that if benefits go up in line with earnings rather than inflation, the average lone parent with one child will be £351 worse off a year.
Couples with two children will miss out on £312, while single people with no children will lose £186 and couples with no kids will be £316 worse off.
Rebecca McDonald, chief economist at the Joseph Rowntree Foundation said: “The majority of the public have taken a clear view already, and firmly oppose government suggestions that they are considering the biggest permanent real-terms cut to the basic rate of benefits ever made in a single year.
"This is all the more decisive when you consider that the issue has only been in the public eye since the government first floated the idea for the real-terms cut less than a fortnight ago."
She said that support for an inflation-level rise is clear across all age groups, income groups and regions, adding: "The Prime Minister must surely realise that her refusal to confirm the uplift is completely out of step with public opinion and the times in which we are living.
“Pressing ahead with this move in the face of public opposition would be morally indefensible and would target spending cuts at those on the lowest incomes, many of whom cannot afford the essentials as it is. It would also terrify millions who have already been enduring a cost of living emergency for months.”
Ms Truss insisted earlier this week: “No decision has been made yet on benefit uprating.”
"There will be a national uprising if this goes ahead because it is nothing to do with making the growth policies of the Government work, it is simply making the poor pay the price,” fumed former Labour PM Mr Brown.
"It's divisive because we're not in this together anymore, it's anti-work because 40% of those who would suffer are people on low pay in work, it's anti-family because five million children would be in poverty - and I think most of all it's immoral.
“It's asking the poor to bear the burden for the crisis that we face in this country and for mistakes that other people have made, and it's a scar on the soul of our country, it's a stain on our conscience."
A dizzying line-up of Tories demanded a welfare rise with inflation - ranging from right-wingers Esther McVey and Lord Frost, to centre-right Damian Green, Mel Stride and Michael Gove.
“The Government shouldn't take on battles it can't win,” said Lord Frost.
Serving Cabinet ministers Penny Mordaunt and Robert Buckland urged a rise with inflation - and more raised fears in private, a No10 insider said.
The insider added: “The policy is… dynamic”.
