Kemi Badenoch will today demand a face-to-face meeting with Sir Keir Starmer to work together on cutting Britain's soaring benefits bill.
Ms Badenoch will be offering up the Conservative Party's support "in the national interest" to slash welfare after Labour's left-wing rebels forced a Government U-turn earlier this year.
The Government eventually passed its benefits bill by 75 votes, but only after offering last-minute concessions to the rebels.
In a speech on Tuesday, the Tory chief will say: "If we're to cut spending and avoid more punishing tax rises at the Budget, crushing business confidence and pushing up inflation, Keir Starmer has to change his approach."
She, Shadow Chancellor Sir Mel Stride and Shadow Welfare Secretary Helen Whately want in-person talks with Sir Keir, Rachel Reeves and new Work and Pensions Secretary Pat McFadden.
Kemi Badenoch will demand a triple head-to-head with the PM, Chancellor, Work & Pensions Secretary and their shadow counterparts
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The trio "are making him a clear offer", Ms Badenoch will say. "Sit down with us."
"Let's agree a way to bring welfare spending down... And I will offer him the support of the Conservative Party.
"This isn't a blank cheque... It's an offer to work together in the national interest and to find common ground and a serious plan.
"I hope the Prime Minister will put country before party and agree to work across the aisle on this."
She will also reaffirm her party's commitment to the two-child benefit cap, which the PM is facing backbench calls to scrap.
If the two parties meet and come to an agreement, the Tories' 120 MPs could avert another humiliating U-turn.
Though the Conservatives all either voted against or abstained on Labour's welfare Bill on July 1.
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'I hope the Prime Minister will put country before party and agree to work across the aisle on this,' Ms Badenoch will say
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And Mr McFadden has preemptively declined Tuesday's invitation, pointing to how the Tories "had 14 years to reform welfare".
A DWP source said: "Instead, they left the country with a broken system that holds people back and fails to support the most vulnerable.
"Kemi Badenoch's Tory Party should be apologising for the state they left the system in."
As well as welfare, the Tories will table a plea for Sir Keir and Ms Reeves to not hike taxes this autumn - as the latter is expected to do on landlords and banks.
'Kemi Badenoch's Tory Party should be apologising for the state they left the system in,' a DWP source blasted
| GETTYDoing so would create a fiscal "doom loop", Ms Badenoch will say, which will "push Britain closer to a bond crisis".
Ms Badenoch's "doom loop" warning follows the same from Sir Mel.
Not long ago, the Shadow Chancellor told GB News that impending autumn tax rises would cut Labour's fiscal headroom - then raising them again would cut it again.
"That's the vicious cycle," he said.
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