Prime Minister Sir Keir Starmer will give his backing to the Chancellor’s Budget in a speech on Monday and commit the government to go “further and faster” on pro-growth measures.
He will say Chancellor Rachel Reeves’ statement will help ease cost of living pressures, reduce inflation and ensure economic stability.
It comes as the Treasury faces questions over whether it was transparent about the state of the public finances in the run-up to the Budget.
Conservatives claimed Reeves misled the public by being too pessimistic about the economic outlook when official forecasts painted a more optimistic picture.
No 10 has denied that Reeves misled voters and defended his statement.
Despite the Office for Budget Responsibility (OBR) downgrading growth from next year, the Prime Minister will argue that “economic growth is outperforming forecasts” but the government must do more to encourage it.
Sir Keir is expected to say that protecting investment and public services will further boost financial growth.
The Prime Minister will also promise to reduce “unnecessary bureaucracy” in infrastructure after a report found the UK had become the most expensive place in the world to build nuclear energy infrastructure.
It calls for reforms in the sector and an urgent correction of “fundamentally wrong environmental regulation.”
Business Secretary Peter Kyle will be tasked with applying the lessons of the nuclear energy report to infrastructure more widely.
The Prime Minister’s speech on Monday, just five days after the budget, may suggest some nervousness about how the government’s economic plans have been received by the public, although No 10 says a statement had already been planned.
In the days after the budget, Downing Street was forced to publicly back Reeves after her political opponents accused her of repeatedly warning of a downgrade to the UK’s economic productivity forecasts, paving the way for tax rises.
In a letter sent to MPs on Friday, the OBR chairman revealed that he had told the Chancellor on September 17 that the public finances were in a better position than previously thought.
Conservatives accused Reeves of giving an overly pessimistic impression of public finances as a “smokescreen” for raising taxes.
Conservative leader Kemi Badenoch said the letter showed Reeves had “lied to the public” and should be sacked.
Last week, a Treasury spokesman said: “We are not going to go into the OBR processes or speculate on how that relates to internal decision-making in preparing a budget, but the chancellor made her decisions to reduce the cost of living, reduce hospital waiting lists and double the margin to reduce the cost of our debt.”
Both the chancellor and Badenoch will appear on the BBC’s Sunday program with Laura Kuenssberg.
