The Government will formally drop its ill-fated cuts to disabled benefits tomorrow in the wake of Iain Duncan Smith's dramatic resignation.
New Work and Pensions Secretary Stephen Crabb will tell the Commons in a statement that the curbs to Personal Independence Payment (PIP) have been abandoned.
The move comes after a turbulent day of Tory infighting that saw Mr Duncan Smith condemn Chancellor George Osborne's "arbitrary" cap on welfare spending and obsession with "short term savings".
Speaking on the BBC's Andrew Marr show, the former Conservative leader insisted his decision to quit the Cabinet was not "personal" or a "secondary attack" on the Prime Minister.
He said he felt the party was undermining its "one nation" ambitions by balancing the books on the back of the working age poor and vulnerable. The final trigger for his resignation was learning that Mr Osborne had "juxtaposed" the £1.3 billion a year PIP curbs with tax cuts for the better off in the Budget.
"The truth is yes, we need to get the deficit down, but we need to make sure we widen the scope of where we look to get that deficit down and not just narrow it down on working age benefits," Mr Duncan Smith said.
"Because otherwise it just looks like we see this as a pot of money, that it doesn't matter because they don't vote for us."
Mr Duncan Smith flatly denied that his decision had anything to do with personal animosity to Mr Osborne or his desire for Britain to leave the EU, describing that as "the most puerile idea I have ever heard".
Energy Secretary Amber Rudd told Sky News' Murnaghan programme she had "respect" for Mr Duncan Smith but his behaviour was "really disappointing".
"I do resent his high moral tone on that when the rest of us are absolutely committed to a one nation government," she said. "I do find his manner and his approach really disappointing."
Pensions minister Lady Altmann accused her old boss of "shocking" behaviour and trying to inflict "maximum damage" on the party leadership to get Britain out of the EU.
But colleagues Priti Patel, Justin Tomlinson and Shailesh Vara lined up to hit back at Lady Altmann.
Employment minister Ms Patel told BBC Radio 5 Live's Pienaar's Politics the departure was "not about Europe".
"With respect to Ros ... what I would like to say is that working with Iain he has always provided support and encouragement in all that we have done as a ministerial team," she said.
Tory backbencher Heidi Allen questioned whether Mr Osborne should continue as Chancellor.
"It depends how he responds to that challenge. I'm hoping so, but we'll see in the weeks and months ahead," she told the BBC's Sunday Politics.
Shadow chancellor John McDonnell insisted Mr Osborne now had to "rip up" the financial package. "George Osborne needs to come back to Parliament now, pull this Budget and start again because this Budget isn't sustainable any more," he told BBC Radio 5 live.
Labour is likely to table an urgent question in a bid to force the Chancellor to come to the Commons.
Prime Minister David Cameron is also due to make a statement to MPs on last week's Brussels summit, where a new deal aiming to tackle the migrant crisis was agreed.