Darren Jones is asked how damaging it is to see newspaper quotes from his own party's ministers describing the handling of the Budget as a "disaster" and calling Reeves and Starmer "weak and incompetent".

Jones says "it's not for me to tell my colleagues that briefing against yourself is a bad idea", but he rejects the premise of the question.

Asked whether it has damaged trust in the government, Jones says briefings to the press damage trust - but he insists "the Budget has brought stability back to public finances and the economy".

Darren Jones, the chief secretary to the prime minister, is asked whether the chancellor lied in the lead-up to the Budget.

"No, of course she didn't," he replies.

Pushed on the question again, Jones holds firm. He says Reeves had three clear priorities going into the Budget: to tackle the cost of living, protect investment in the NHS, and get debt falling as a share of the economy.

She "ticked all of those boxes", he says.

When asked again how honest Reeves was in the lead-up to the Budget - and whether she misled the public by suggesting the public finances were in a worse state than they were - Jones explains how the Office for Budget Responsibility's forecasting process works.

There are five rounds of forecasts, he says. Numbers are updated on a "continuous basis" with decisions taken by the chancellor in the final week or so before the Budget.

The £4bn "headroom" revealed in one of these forecasting rounds was "too small", he adds.

Jones says the government needed to increase its headroom to £20bn and pay for the decisions it took on cost-of-living measures and the NHS.

The Chief Secretary to the Prime Minister, Darren Jones, is speaking to BBC Breakfast now. Watch live at the top of the page and stay here for key lines.

Kemi Badenoch has reiterated her calls for Rachel Reeves to resign for her pre-Budget messaging.

The Conservative leader told the BBC's Laura Kuenssberg on Sunday: "The chancellor called an emergency press conference [on 4 November] telling everyone about how terrible the state of the finances were and now we have seen that the OBR had told her the complete opposite.

"She was raising taxes to pay for welfare.

"The only thing that was unfunded was the welfare payments which she has made and she's doing it on the backs of a lot of people out there who are working very hard and getting poorer.

"And because of that, I believe she should resign."

Badenoch's comments comes after she labelled Reeves "spineless, shameless and completely aimless" during the Budget debate.

The Conservative leader accused Reeves of breaking promises not to raise taxes - and accused her of "whining about mansplaining" and misogyny.

Meanwhile, Reform UK leader Nigel Farage has reported Reeves to the independent adviser on ministerial ethics to investigate whether she broke the ministerial code over her pre-Budget interventions.

Reeves is facing accusations that she misled the public in the lead-up to the Budget, by suggesting the public finances were in a worse state than they actually were.

In a pre-Budget speech on 4 November, Reeves strongly hinted at tax rises, saying she would make the "necessary choices".

It was "clear" that the UK's productivity performance was "weaker than previously thought", Reeves said.

But a letter from the OBR, external, sent to MPs on Friday, has - her critics say - challenged this narrative.

It reveals that a forecast of higher wages would help offset the effects of the productivity downgrade - something Reeves did not mention.

It also appears she was on track to meet her fiscal rules by 2029/30.

On 31 October, the OBR told the Treasury it was on course to meet its rule of not borrowing to fund day-to-day spending - albeit by £4.2bn less than the £9.9bn in "headroom" (or "buffer") Reeves left herself last year.

Reeves delivered her pre-Budget speech just four days later.

Tory leader Kemi Badenoch said the letter showed Reeves had "lied to the public" and should resign.

Reeves has denied misleading the public. "I clearly could not deliver a budget with just £4.2bn of headroom," she told the BBC's Laura Kuenssberg on Sunday, saying that would have been "the lowest surplus any chancellor ever delivered".

Image source, Reuters

The prime minister will focus on welfare reform when he speaks in London later today.

His speech comes after the government was, earlier this year, forced to U-turn on its plans to narrow eligibility for Personal Independent Payments (PIP), following a backbench rebellion.

"We have to confront the reality that our welfare state is trapping people, not just in poverty, but out of work," he will say. "Young people especially. And that is a poverty of ambition."

He will argue reforms are not aimed at making him "look somehow politically 'tough"', but at reversing low productivity.

"And so while we will invest in apprenticeships and make sure every young person without a job has a guaranteed offer of training or work, we must also reform the welfare state itself - that is what renewal demands."

The PM will also highlight the scrapping of the two-child limit - forecast to take 450,000 children out of relative poverty in five years' time - which was announced by Rachel Reeves last week.

And he will say "economic growth is beating the forecasts" but the government must go "further and faster" to encourage it.

He will promise to cut "unnecessary red tape" in infrastructure, after a report found the UK had become the most expensive place in the world to build nuclear power.

Nathan Williams
Live page editor

Good morning and welcome to our live coverage, ahead of a speech by the prime minister later this morning.

Keir Starmer will warn that benefits are "trapping" people in poverty, while stressing the need for welfare state "reform".

The PM will also back Chancellor Rachel Reeves, who has denied that she misled the public about the state of the UK's finances in the run-up to the Budget. The Conservatives have called on her to resign.

Stay with us as we take you through the build-up to the speech - including hearing from Darren Jones, chief secretary to the PM, who's speaking to the BBC this morning.