New Work and Pensions Secretary Stephen Crabb has said there will be no further raid on welfare spending to fund the £4 billion black hole in the Budget left by the dramatic decision to abandon planned cuts to disability benefits.
Making his first appearance in the Commons since his appointment in the wake of the bombshell resignation on Friday of Iain Duncan Smith, Mr Crabb said there were "no further plans" for welfare savings beyond the Welfare Reform and Work Act.
"We won't be seeking alternative offsetting savings and ... we are not seeking further savings from the welfare budget," he told MPs.
Earlier David Cameron sought to defend under-fire Chancellor George Osborne - insisting that he deserved the credit for turning round the economy.
He also sought to begin the process of healing the deep wounds opened up by the departure of Mr Duncan Smith, praising his welfare reforms and reaffirming his commitment to "compassionate Conservatism".
However the Chancellor came under fire from Labour leader Jeremy Corbyn, who said the decision to abandon the planned cut to Personal Independence Payments (PIPs) had left an "enormous hole" in his Budget plans.
He called on Mr Osborne to come to the House to explain why "for the first time in my memory in Parliament, a Government's budget has fallen apart within two days of its delivery".
Mr Cameron played down Mr Osborne's decision not to answer a Commons emergency question by shadow chancellor John McDonnell on the changes himself - leaving it to junior Treasury minister David Gauke - saying the Chancellor would wind up the Budget debate on Tuesday.
Earlier however Downing Street disclosed that Mr Osborne would not now be bringing forward alternative measures to meet the shortfall left by the cancellation of the cuts to PIPs until the Autumn Statement at the end of the year.
Mr Cameron also sought to defuse a damaging backbench revolt, confirming that ministers would not seek to oppose amendments to the Budget on the so-called "tampon tax" and VAT on solar panels.
Some Tory Eurosecptic MPs had signalled they intended to vote with Labour in an attempt to embarrass the Government over the role of the European Union in setting VAT rates ahead of the referendum on June 23.
However the Prime Minister's official spokeswoman said EU leaders had now agreed that VAT could be scrapped on women's sanitary products while the amendment on solar panels simply confirmed the current position while consultations were ongoing.