Rachel Reeves has pledged to take “an iron fist against waste” as she launches a Whitehall efficiency drive.
The chancellor said she would “inspect every pound” spent by the government to make sure it was providing value for money.
Cabinet ministers will also have to show that all of their spending plans are aimed at delivering the “plan for change” unveiled by Keir Starmer last week.
The prime minister vowed to make people better off, build 1.5 million homes, get more children ready to start school, bring down hospital waits, recruit thousands more neighbourhood police and de-carbonise the electricity grid by 2030.
All other Whitehall projects which are already in the pipeline will be cut as the government continues its efforts to fill a £22 billion black hole in the public finances left by the Tories.
Reeves said: “By totally rewiring how the government spends money we will be able to deliver our plan for change and focus on what matters for working people.
“The previous government allowed millions of pounds of taxpayers’ money to go to waste on poor value for money projects. We will not tolerate it; I said I would have an iron grip on the public finances and that means taking an iron fist against waste.
“By reforming our public services, we will ensure they are up to scratch for modern day demands, saving money and delivering better services for people across the country. That’s why we will inspect every pound of government spend, so that it goes to the right places and we put an end to all waste.”
Whitehall budgets will also be scrutinised by former senior management at private sector companies like Lloyd’s and Barclays Bank to make sure they are cutting out waste, the Treasury said.
Darren Jones, the chief secretary to the Treasury, will set out the new regime in letters being sent to all cabinet ministers today.
A Treasury source said: “Departments will be advised that where spending is not contributing to a priority, it should be stopped.
“Although some of these decisions will be difficult, the chancellor is clear that the public must have trust in the government that it is rooting out waste and that their taxes are being spent on their priorities.”