Kevin Craven, chief executive of the ADS Group, the UK’s trade body for the aerospace, defence, security and space sectors, says Healey's resignation has "sent us reeling".

In a statement, he says the now former defence secretary "has consistently shown himself to be an intelligent, supportive and highly principled man, who has the best interests of UK defence as top of mind in everything that he does."

Craven adds: "His resignation today is something to lament, and is truly a damning reflection on the current state of affairs."

He warns that the consequences of getting the defence investment plan wrong "are of a magnitude far beyond our worst fears", adding that it's "imperative that an adequately funded Defence Investment Plan is published as soon as possible."

"It should not take the resignation of an honourable man for that realisation to sink in."

The number of soldiers, ships, and fighter jets has fallenpublished at 14:52 BST

14:52 BST

By Adam Durbin and Thomas Spencer

Since the end of the Cold War in 1990, the British Army has gone from having 153,000 regular soldiers to 73,790 today - only just above the 73,000 minimum recommended in last year’s strategic defence review.

As well as the regular Army there have been reductions across the military over the same period:

• Army reservists have gone from 76,000 to 25,770
• The Royal Navy has fallen from 48 major combat ships (13 destroyers, 35 frigates), to 13 (seven frigates and six destroyers)
• The Royal Air Force has dropped from more than 300 combat jets to 144

It is important to note, however, that these newer fighter jets - 107 Eurofighter Typhoons and at least 37 F-35 Lightning IIs - are technologically superior to those in use 36 years ago.

And uncrewed aircraft systems, also known as drones, now form an element of the UK's military air capabilities. These did not exist in 1990.

Experts say the UK needs to invest considerably more in this military technology. Read more of BBC Verify’s analysis of the state of the UK military here.

Faisal Islam
Economics editor

John Healey’s resignation reflect some bruising internal negotiations with the chancellor over finding the money to fund the defence investment plan. The now former defence secretary confirmed that the level of spending would reach 2.68% of GDP by 2030.

His letter also acknowledged that other departments would face some cuts against their plans. It is thought that this is a reference to the capital budgets for transport and energy, among other things. Defence spending, on heavy equipment and technology, is very capital intensive.

A Treasury source told the BBC that Chancellor Rachel Reeves will always do what is right and needed to keep this country safe".

The source pointed to a "record uplift in defence spending at the spending review”, and said Reeves would be "working alongside the PM deliver billions more to fund the defence investment plan in full".

As leadership speculation looms over the government, it is worth noting that Greater Manchester Mayor Andy Burnham previously suggested that some defence spending could be exempted from fiscal rules, as has occurred in Germany.

His advisers have suggested this may occur over a longer time period, only after the UK balances its budget.

The Spanish PM Pedro Sanchez, who publicly refused to meet the 3.5% Nato target, is now publicly citing this move as one of the reasons behind Spain’s strong economy.

Image source, PA Media

"Labour has no serious plan to address threats we face," says leader of the Green Party Zack Polanski.

He calls it "a government with no leadership, under a caretaker PM expected to be replaced imminently - it's chaos".

Polanski adds: "We need to make sure that we're looking at defence to also include cyber security, threats to nature and the climate crisis and our resilience towards both pandemics and terrorist attacks.

"Most of all we need a clear and consistent plan."

Shock within Labour at resignation of 'loyalist's loyalist'published at 14:26 BST

14:26 BST

Henry Zeffman
Chief political correspondent

The main emotion I am getting from Labour ministers, MPs and advisers right now is shock. This isn’t very John Healey.

He has been a Labour MP since 1997, serving either as a minister or a shadow minister under every Labour leader in that time - and there have been several, of quite a few different political hues.

More specifically, he’s overseen the defence brief for Keir Starmer for the entirety of Starmer’s six years as Labour leader - a period in which the world has become more war-torn and more dangerous.

In public but also in private, he plays a straight bat.

"He was the loyalist’s loyalist," one Labour figure who worked with Healey closely in this job said to me.

Yes, there were signs that he was frustrated. Signs that, as with any defence secretary but especially at a time like this, he wanted the government to spend more on defence.

But few seem to have had any sense at all that he had frustrations on this level.

Speaking to Vicki Young on Politics Live, the former Chancellor Jeremy Hunt says that John Healey has been "very brave and principled" in resigning.

Hunt says it was clear Healey had lost the Whitehall battle to increase defence spending by £28bn. If the government is to keep the country safe, he says, "the prime minister now needs to find that money".

He adds: "There’s only one game in town - if you need to find the money quickly, it is to bite the bullet on welfare reform."

Image source, Getty Images

Wes Streeting, who quit as health secretary last month citing a lack of confidence in Keir Starmer's leadership, has shared a short statement on X.

"John was an excellent Defence Secretary. Every word of warning here needs to be heeded."

Henry Zeffman
Chief political correspondent

Nearly two hours after John Healey’s resignation, the government has issued its first response, via a source.

The source said: "This country is safer because of the decisions Keir Starmer has made and we will continue to act in our national interest.

"It is this Labour government and this Labour prime minister that is delivering the largest sustained boost to defence spending since the Cold War.

"We cut the international aid budget to make record investment in our armed forces, and now the PM is imposing cuts on other government departments to fund billions more.

"The defence investment plan will deliver the capability our armed forces need. ⁠We will always do what is right, and needed, to keep the country safe."

We continue to see political reaction pour in following John Healey's resignation.

Dave Doogan, the SNP's representative in Westminster, says that "once again, the Labour Party is engulfed in chaos".

He adds that it is "yet another sign of a government losing control".

Plaid Cymru's Westminster Leader, Liz Saville Roberts, says the resignation "is another blow to the prime minister’s credibility and authority. These really are the dying days of Starmer’s government."

Image source, House of Commons

This raises stark questions about Starmer's authoritypublished at 14:01 BST

14:01 BST

Henry Zeffman
Chief political correspondent

This is devastating for Keir Starmer.

It would be devastating for any prime minister at any time, whatever their general political condition, to have the defence secretary resign and denounce how seriously they take defence of the realm.

But clearly at a time of global conflict and at a time of internal Labour Party conflict, with Starmer’s position more vulnerable than it has ever been, it is an especially devastating decision for Healey to have made.

Starmer had planned to fill the gap between now and next Thursday’s Makerfield by-election, which may well return Andy Burnham to Westminster, with policy: with signs that he is getting on with the job as prime minister and still has the authority to do things.

The defence investment plan was meant to be at the heart of that plan.

It is very hard to see how it can now be published in its current form, even with a new defence secretary.

That inevitably raises stark questions for Starmer about his authority to go on leading this government.

Image source, PA Media

Al Carns, the armed forces minister, says John Healey took on the defence ministry "at a moment when the world was getting more dangerous, not less, and he carried that weight with the discipline and decency that the job demands".

In a statement online, he says he worked with Healey closely, observing the "hours, the care and the seriousness" he brought to the role.

The Labour MP says there are "issues" facing the defence department, "that do not lend themselves to easy answers".

"Our armed forces remain on operations around the world, standing with our allies, protecting our interests, and keeping the British people safe. They deserve a Ministry of Defence that matches their seriousness with our own. That is the job. It continues today."

Image source, Getty Images

Former Defence Secretary Penny Mordaunt says in a post on X that John Healey recognises "this moment for what it is.

"Pivotal for our national resilience and defence with devastating consequences if we fail to modernise and rearm. Thank you John. Country before party."

This row between No 10, the Treasury, and the military has been going on for monthspublished at 13:48 BST

13:48 BST

Jack Fenwick
Political correspondent

This is the latest and most dramatic twist in a saga about defence spending that has been going on for months.

Last June the government published its strategic defence review – a document which set out how to ensure the UK was ready for war.

Another document – the defence investment plan – was supposed to follow last autumn. It would lay out how the government would buy the necessary equipment to make its defence ambitions a reality – and crucially how much money would be involved.

But that document has never seen the light of day – largely because of a huge row involving the Ministry of Defence, the Treasury and Number 10 over how much extra cash the country could afford.

The prime minister told MPs in March that the investment plan was on his desk – a clear insinuation that its publication was imminent.

But since then, there’ve been further delays, as the government has attempted to figure out where it could cut money in other areas to fund defence.

And the nature of the arguments with the Ministry of Defence have become increasingly bitter.

The arguments spilled out into the public realm for the first time in April, when Lord Robertson – a Labour peer, former Nato boss and author of the government’s defence review – launched a scathing attack on ministers and called for a cut to welfare to fund the increase.

Number 10 hoped that it had reached something of a compromise when it presented John Healey with a plan on Monday – but Healey decided the money involved wasn’t an offer he could accept.

Image source, Pool

Leader of the opposition Kemi Badenoch says she is "not surprised" John Healey has resigned, calling his decision "the honourable thing".

She says she asked the PM about defence spending at PMQs yesterday, and Starmer - according to Badenoch - exposed that he was "not going to put money into defence to the amount that was required".

"I am glad that he [Healey] agrees with me," she says, but calls his letter "shocking" in suggesting current spending plans could leave troops at risk.

Badenoch says Starmer is "putting in less than half of the minimum required", with last year's strategic defence review suggesting about £28bn was required.

She says he is "more interested in saving his job" by appeasing backbenchers with welfare spending than "putting the national interest first".

Badenoch says the country needs to spend 3% of GDP on defence by the end of this parliament - claiming her party would fund this by reinstating the two-child benefit cap and implementing a sovereign defence fund.

Jack Fenwick
Political correspondent

BBC News understands that John Healey has asked the government's other defence ministers to stay in post to minimise disruption.

Jonathan Beale
Defence correspondent

The BBC understands that John Healey had been pressing the prime minister for a larger increase in defence spending than he was offered.

The deal the prime minister offered on Monday did not include a timetable to reach 3% of GDP.

Having promised to reverse what he called the "hollowing out" of the armed forces, the settlement John Healey was offered on Monday was not enough.

In other words, it would have meant further cuts.

Healey was being offered an extra £13.5bn over the next four years - which defence sources said would really mean a £10bn increase alongside some "treasury trickery".

The offer was well short of what Healey had been asking for - and well below the estimated £28bn needed to avoid large cuts.

It’s understood that Healey told the prime minister that what amounted to a 0.08% increase would not be enough to keep the country safe.

Image source, Getty Images

"Healey's resignation is a wake-up call for Starmer and Burnham," Liberal Democrat leader Ed Davey says.

In a post on X, he adds: "Stop repeating the mistakes of the Conservatives and get serious about funding our armed forces properly.

"We cannot afford years more political chaos while our national security is put at risk."

Shadow Defence Secretary James Cartlidge says John Healey has shown "integrity" by resigning and tells the prime minister he is "paying the price" for prioritising welfare over a stronger military.

In a video posted online, he says Healey was "left with no choice" as the government was offering him "such a tiny amount of money" for the armed forces.

"This is not good enough," he adds.

By how much has the UK's defence spending been increasing?published at 13:19 BST

13:19 BST

By Ben Chu

On 25 February 2025, Prime Minister Keir Starmer announced that UK defence spending would rise to 2.5% of GDP in 2027, funded by aid spending being cut from 0.5% of GDP to 0.3% in the same year.

And the government said that, including spending on the UK’s security and intelligence agencies, the overall defence budget would reach 2.6% of GDP by 2027.

The UK’s estimated Nato-qualifying defence spending - which is the spending that the military alliance counts as meeting its members’ commitments - was 2.3% of GDP in 2024 and 2.4% in 2025.

In February 2025, Starmer also stated an "ambition" to increase defence spending to 3% of GDP "in the next parliament".

At a summit in The Hague in June 2025, the UK and other Nato members committed to spending 3.5% of GDP spending on defence by 2035.

John Healey’s resignation letter as defence secretary suggests the planned defence investment plan intends to increase defence spending in 2030 to 2.68% of GDP.

That implies an 0.08% increase on the existing 2027 commitment of 2.6% of GDP - around £2.4bn in today’s money.

The exasperation is clearpublished at 13:08 BST

13:08 BST

Chris Mason
Political editor

What is already becoming very clear is the exasperation, frustration and anger that has led to this moment.

Senior figures in the armed forces were making it clear that the funding being suggested was nowhere near enough.

As had been widely reported, the figure in question was an increase of around £13.5bn in the next four years.

Plenty reckoned this was inadequate, not least because in their view it wasn’t even £13.5bn - but actually around £10bn, with the remainder disparagingly dismissed as accounting trickery from the Treasury.

Let’s see how the Treasury and No 10 respond.

An ally of the - now former - defence secretary says: "Healey has been one of the most loyal Labour men for over 30 years. He’s only ever wanted a successful Labour government."