Angela Rayner will unveil an overhaul of planning rules next week as Labour seeks to clear a path to building 1.5 million homes in five years.

The Deputy Prime Minister and Housing Secretary said that “delivering social and affordable houses at scale” is her “number one priority”.

But the planning system should be “a launchpad” rather than a “millstone” dragging down the housing market, she wrote in The Observer.

The overhaul, to be announced before MPs leave for summer recess, will include bringing back mandatory housing targets that were scrapped by the previous Government and introducing “golden rules” to ensure development works for local people and protects nature, Ms Rayner said.

“We plan to set out in detail more of these early and important changes in an updated National Planning Policy Framework next week,” Ms Rayner wrote.

She said the Government was committed to preserving the green belt and will prioritise building on the so-called grey belt – green belt land that has previously been developed and includes disused car parks and wasteland.

She also said that Labour knew there was a housing emergency when they came into power, but that “lurking under each stone we lift” is “a frankly scandalous legacy” left by their Conservative predecessors.

Ms Rayner’s planning announcement will come as Chancellor Rachel Reeves is expected to unveil a black hole in the public finances of around £20 billion.

The Chancellor will outline the spending inheritance left by the Tories when she presents the results of a Treasury audit to Parliament on Monday.

A government spokesperson said the audit had shown “the previous government made significant funding commitments for this financial year without knowing where the money would come from”.

The spokesperson added: “The assessment will show that Britain is broke and broken – revealing the mess that populist politics has made of the economy and public services.”

The Chancellor is expected to approve above-inflation pay rises for millions of public sector workers in response to the recommendations of independent pay review bodies.

Teachers and some 1.3 million NHS staff could be in line for a 5.5% pay boost, which could cost about £3.5 billion more than had been budgeted for.

This could rise to about £10 billion if other pay review bodies give similar advice on workforces such as police and prisons officers and doctors and dentists, according to the Institute for Fiscal Studies (IFS).

As this cost has not been fully budgeted for in current plans, the cash would have to be raised through existing fiscal headroom, tweaking fiscal rules or tax increases.

Any tax hikes to meet those costs would not be expected before the autumn budget, the date of which Ms Reeves is also set to announce on Monday.

Labour has ruled out lifting income tax, VAT, national insurance and corporation tax, potentially leaving changes to pensions relief and capital gains and inheritance levies on the table.