Defence Secretary Dan Jarvis said there would have to be "conversations" with the next PM about funding the armed forces

Mr Jarvis also insisted it was not "unreasonable" to set out those plans at a "major fiscal event".

This morning, Mr Jarvis said: "I think we made really good progress yesterday with the publication of the plan, and that was helpful because it ended the uncertainty that had been around it.

"But yes, I will want to do more and go further, and it’s my job, working with the chiefs, to make sure that we secure the resource, the investment that we need into defence to honor the commitments that we have made, which I am absolutely determined that we will keep.

"I think, though, it is not unreasonable to accept the basic point that when you are committing billions and billions of pounds of investment, that in the normal order of business those kind of commitments are made in the context of a major fiscal event.

"There will be a spending review next year. I will be making the case for defence. I’m sure that that is a case that will be supported very closely by the Chiefs.

"Obviously, there will be conversations that will have to be taking place with the person who’s going to be the next prime minister, but fundamentally, my job is to fight hard for defence. That’s what I’ve done for the past two weeks, and that’s what I intend to keep doing."

The Defence Secretary said he had "assurance" that Andy Burnham would ensure investment in defence.

During a visit to Cambridge Aerospace, Dan Jarvis told reporters: "I absolutely have the assurance that, as prime minister, Andy Burnham will make sure that we've got the investment coming into defence.

"That is good for our nation, good for our national security, but it's also good for economic prosperity and its companies and workers in this part of the country that I think will benefit very well from the new investment that we’ve announced."

John Swinney has rejected Andy Burnham's claim that parts of Scotland feel as distant from Holyrood as they do from Westminster.

The First Minister said the Labour MP is not in a "strong position to lecture" him. Swinney also said he does not agree with the idea of creating mayors in Scotland, similar to the role Mr Burnham held before his election to the Commons.

Mr Burnham, who looks set to succeed Sir Keir Starmer as prime minister this month, has pledged to increase devolution across the UK with plans for a "Number 10 North" to redistribute power.

The Makerfield MP said: "Its job will be to make power flow into places like Glasgow, Aberdeen, Dundee, Paisley and Easterhouse, not hold it back."

In a speech earlier in the week, the former Manchester mayor said people in Dundee and Bangor "feel just as distant from Holyrood and the Senedd as they do from Westminster".

Swinney, on Wednesday, said: "I don't agree with them that areas feel distant from Holyrood. The city of Dundee just re-elected SNP members of the Scottish Parliament and the Labour Party got terrible results in the city.

"I don't really think Andy Burnham is in a strong position to lecture me about all of these questions.

"I think rather than offering us these polemics, if Andy Burnham is going to become the prime minister, he should have a substantive discussion with the Scottish Government and me about how we empower and strengthen the powers of the Scottish Parliament, and I'll be a willing partner in doing that."

John Swinney in the Scottish Parliament(Image: Getty Images)

Mirror Political Correspondent Sophie Huskisson writes in with the three questions the PM faces over defence spending…

1) Is the £15billion military spending boost enough?

Some military voices have warned the £15bn funding for the Defence Investment Plan (DIP) is well below the £28bn defence chiefs had originally requested. They warn the plan does not set out how the UK will hit its target to spend 3% of GDP on defence nor its Nato commitment of 3.5% by 2035.

Former Defence Secretary John Healey warned the DIP fell short of what was needed to see off the threat from Vladimir Putin. He said Britain will “still be spending just 2.7 per cent of GDP in 2030, the date when Nato has warned we could face a Russian attack”. Max Warner, a senior research economist at IFS, said the Government needs to set out a path to 3.5% of GDP spent on defence by 2035, which he said will cost around an additional £25billion each year.

2) Is the Defence Investment Plan fully funded?

In short, no. This leaves a huge headache for Andy Burnham, who is widely expected to take over from Keir Starmer in Downing Street.

As journalists trawled over the small print of the DIP on Tuesday, we spotted that £4.7billion - almost a third of the £15bn plan - will need to be funded in the Budget. It is understood that Mr Burnham was not told about the black hole when he was briefed on the plans, which experts said could force him to consider tax rises, more borrowing or spending cuts.

Defence minister Luke Pollard this morning said the £4.7bn black hole in the plan was “not unusual”. But Mr Starmer is likely to face some tough questions on the funding of the DIP at PMQs.

3) How will the rest of the plan be funded?

Keir Starmer is already facing some pushback over his decision to slash some Government spending in order to fund defence.

The PM admitted some road and energy projects which “are important but not immediately vital” will be scrapped to support the plan. Foreign Office minister Hamish Falconer criticised “uncertainty” over a road project near his constituency following the announcement.

Mr Starmer warned his successor - likely Andy Burnham - that defence spending must be a priority in any future spending reviews. But the PM-in-waiting is left with very few options to fill the £4.7bn black hole, with tax rises, spending cuts and borrowing all seen as either too risky or too unpopular.

Andy Burnham's plan for a "No 10 in the North" is an "important gesture in the right direction", leading devolution proponent Lord Heseltine has said.

The Tory grandee, who was the first to call for directly elected mayors in 1991, said it could be "very beneficial" to "our entire economy" if the presumptive next prime minister delivered on the broad vision he set out on Monday.

Lord Heseltine backed the proposal of a "No 10 in the North", but suggested that focusing the unit on decentralisation would matter more than its location.

Asked about the plans, he said: "The critical thing is to have a Prime Minister who is committed to the devolution agenda, and without that, the various components of power in Whitehall will fragment and resist.

"Creating a powerful No 10 unit, whether it's in Manchester or in London or anywhere else, is an important gesture in the right direction."

Despite this, he warned against proposals to hand local leaders the power to set and retain business rates in their area, which Mr Burnham has reportedly been advised to consider, arguing that differences in revenue at a local level must be balanced out by some intervention from central Government.

Heseltine added: "If I was advising Andy Burnham now I'd say look, don't tinker around with local income tax or local rates, get on with the job of generating wealth, and that is basically using capital funds."

Andy Burnham acknowledged taxpayer-funded support would be needed to deal with the cost-of-living pressures facing households.

The Makerfield MP, who expected to become PM, set out his vision and plan for the UK.

He said: "Ours is a 10-year mission to raise people's living standards. I know people can't wait forever for change.

I heard on doorsteps in Makerfield how people need a bit extra now to help with rising costs.

"I will do my very best to deliver it, and whilst not taking risks with the public finances, will seek to give Britain some breathing space as soon as I can.

"People need to be able to look forward to a night out or a holiday with the kids. People need hope."

Burnham delivers a speech at the People's History Museum in Manchester(Image: AP Photo/Alastair Grant)

Mirror Political Correspondent Sophie Huskisson writes in with her expectations of this week’s PMQs…

At PMQs last week, Keir Starmer joked he would miss his exchanges with Kemi Badenoch after the Tory leader bombarded Labour with a barrage of criticism.

Ms Badenoch did not hold back on her vicious attacks on Labour MPs and Cabinet ministers, as she targeted senior figures on the frontbench with bitter and harsh jibes. She asked Mr Starmer if he felt he’d been “betrayed” by his MPs and described Labour ministers as “traitors and deserters”.

At one point, Speaker Lindsay Hoyle was forced to intervene to remind members to show “respect” to one another.

It sparked a tense conversation afterwards when Bridget Phillipson and Liz Kendall confronted Ms Badenoch after the Tory leader branded the Education Secretary a "spiteful class warrior".

The PM can expect forceful attacks again this week, with Ms Badenoch likely to seize on the fallout from the defence investment plan. Mr Starmer faces questions after it emerged there is a £4.7billion funding shortfall, which will be left for PM-in-waiting Andy Burnham to fill.

Remember when Keir Starmer and Rachel Reeves repeatedly criticised a £22billion black hole left behind by the Tories after the 2024 general election? That attack line could come back to bite.

Andy Burnham gave his first major speech since Keir Starmer announced his resigation.

On Monday, the Makerfield MP, said he will lead a decade-long plan to transform Britain by transferring power out of Whitehall and giving regions more control.

Burnham, who is expected to take over as PM, said the Westminster system was "broken" and "as a result, the country isn't where it should be". He added: "It is stuck in a rut, and clearly we can’t go on like this."

He dubbed the dubbed the disbursement of power as the No 10 North as the "nerve centre of a rewired Britain" to oversee to devolution of power to mayors and local authorities.

Part of this move away from Westminster includes Burnham reportedly intending to still live in Greater Manchester with his family and only staying in Downing Street a few days a week.

Andy Burnham only found out about the £4.7 billion hole in the plan to boost defence spending on the day it was published, the defence minister has suggested.

Minister Luke Pollard, speaking on Sky News, said: "Downing Street have a close dialogue with Andy's team … I understand they've been keeping him close to the process, and told him yesterday when the Treasury published the statement and the breakdown of the financial costs."

He said he only saw the breakdown from the Treasury himself when the defence investment plan was published on Tuesday.

Pollard added: "So I saw the breakdown of the £15 billion for the first time yesterday when it was published by the Treasury, I understand that Downing Street are keeping Andy's team involved with the process."

Minister Luke Pollard has been speaking on the Dip (pictured September 2025)(Image: Getty Images)

Mirror Political Correspondent Sophie Huskisson writes in…

Keir Starmer is facing intense pressure over a £4.7billion funding gap in the defence investment plan.

The long-awaited Defence Investment Plan (Dip) leaves a headache for Prime Minister-in-waiting Andy Burnham as the small print revealed £4.7bn - almost a third of the £15bn pot - will need to be funded in the Budget. It is understood that Mr Burnham was not told about the black hole when he was briefed on the plans, which experts said could force him to consider tax rises, more borrowing or spending cuts.

Armed forces minister Luke Pollard this morning defended the £4.7bn black hole in the plan to raise defence spending as “not unusual”.

Mr Pollard told Times Radio: “The £15billion extra spending power that we now have with the Treasury set out how £10billion or so of that will be spent by asking other departments to cut their capital funding by 1p in the pound and transfer that money to defence. £4.7billion will be set out at the autumn budget, and that’s not unusual for governments to do.”

He said the just over £1 billion extra a year needed would come from the Treasury’s financial headroom “or any other measures that they seek to do in making spending decisions”, saying it was “standard practice”.

He also admitted that the defence investment plan unveiled on Tuesday delayed improvements to housing for armed forces families. “A small amount of the money in the defence housing budget has been moved into the next parliament so we could prioritise the military readiness for our forces now. That was the right tough decision that we’ve taken.”

Of the funding that has already been identified, most comes from reducing other departments' capital budgets by 1%, providing some £4 billion over the next four years.

The Department for Transport and the Department for Energy Security and Net Zero will be forced to find additional savings of £800 million and £2 billion respectively.

This money is expected to come from cancelling or delaying projects, in a move which has already caused some disquiet among MPs concerned about spending that had been promised to their constituencies.

Chancellor Rachel Reeves said another £2.4 billion had been found by the Treasury taking responsibility for the costs of "ongoing international objectives" such as providing security guarantees for Ukraine in the event of a ceasefire.

Some £400 million is expected to be raised by selling off Ministry of Defence land, and another £600 million from "reprioritisation" of the department's existing budget.

Keir Starmer announced £15 billion of spending over the next four years to support the Defence Investment Plan, but the Treasury put off setting out full details of how it would fund the increase.

In a written statement to Parliament, Chancellor Rachel Reeves said only two-thirds of the sum – £10.3 billion – had been identified, while the remaining £4.7 billion would be "confirmed at Budget 2026, in a fair and balanced way".

Andy Burnham, the frontrunner for No 10, was briefed on the Dip before its publication, but reportedly not told about the need to find an additional tranche of funding in his first budget.