Rachel Reeves will not confirm how the Government’s King’s Speech pledges will be paid for until the autumn, i understands.
The Chancellor has promised not to make any extra spending promises without explaining how they will be paid for within Labour’s strict borrowing rules.
But the Treasury is understood to have no plans to set out detailed explanations of the cost of the Government’s legislative agenda before the Budget, which is expected to take place in October.
The King’s Speech, set out on Wednesday, includes plans for 40 pieces of legislation, including policies that are likely to cost the Exchequer additional money.
Two of the biggest, the creation of a National Wealth Fund and Great British Energy, were set out in detail in the Labour manifesto. The two new bodies will cost just over £3bn a year, mostly funded by additional borrowing.
But other policies in the King’s Speech were not costed in the manifesto and may end up imposing an additional cost on the state.
These include new regulators for the railways, the audit industry, football and the private rented sector – as well as more intensive regulation in the water industry and a duty for local councils to keep a register of children who are not in school.
A No 10 spokesman said: “As you would expect, the next fiscal event, spending review etc will obviously set out an update on the fiscal implications of Government policies.
“Clearly, the Government has made a number of specific commitments as set out in the manifesto, things such as the National Wealth Fund, GB Energy, which obviously stand in their own right, and you can see the costings in the manifesto. But more broadly the next fiscal update will set out an update on that.”
Ms Reeves has promised that all future fiscal events will be accompanied by a full forecast by the Office for Budget Responsibility – a measure being called the “fiscal lock”.
She has also commissioned an “audit” of existing Government spending which is likely to be published in the last week of July – but will not include the implications of any new Labour policies.
The Chancellor told Bloomberg TV: “I’m not going to announce any tax breaks or tax changes without saying where the money is going to come from, and we will have a Budget later this year.
“But I also just need to be really clear and honest about the scale of the challenge that we’ve inherited with the public finances. We’re going to have to make difficult decisions. We need to fix the foundations before we can start rebuilding things in Britain.
“But unlike the previous government, I am going to be honest about the scale of the challenge. I’m going to level with people.”
The Institute for Fiscal Studies welcomed the “fiscal lock” but warned that it would not necessarily stop future chancellors from meddling with the public finances.
Senior research economist Ben Zaranko said: “The new government’s ‘fiscal lock’ is broadly sensible but largely performative.
“It is, in effect, a rather theatrical way of promising not to do another ‘mini Budget’ – or at least not to do another mini-Budget without some accompanying independent analysis from the Office for Budget Responsibility.
“This Chancellor could make and keep to that promise without any need for primary legislation, and some future chancellor determined to misbehave could almost certainly find a way to get around it, but it nonetheless serves as a welcome commitment to fiscal transparency.”