Kemi Badenoch will promise to introduce a "golden rule" to get the deficit down and "get our economy back on track" if the Tories win the next election.
During her keynote speech at the end of the Conservative Party's conference on Wednesday, the Tory leader will say her party is the only party "who can be trusted to meet the test of our generation".
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"We are the only party with a plan to get our economy back on trust," she is expected to say.
Ms Badenoch will tell Tory members she would introduce a "golden economic rule" to ensure for every pound saved, half or more will go to reduce the deficit and half will go towards tax cuts or spending to boost the economy.
She will accuse Chancellor Rachel Reeves of doubling the deficit "with her