JOHN Healey has charged Sir Keir Starmer with the most damning accusation it is possible to make of a Prime Minister – failing to keep Britain safe.

If the defence of the realm is the primary duty of any nation’s leader, it now appears at the mercy of .

Britain's Defence Secretary John Healey walking outside 10 Downing Street.Healey is a serious figure respected by both his Labour colleagues and military top brass Credit: Reuters Britain's Prime Minister Keir Starmer and Britain's Defence Secretary John Healey speaking next to a submarine model.Healey’s devastating departure will crash through Downing Street like one of those laser-guided missiles they are refusing to pay for Credit: AFP

The allegation is made all the more grave by the calibre of the man making it.

This is not the ranting of a stroppy minister throwing his toys out of the pram.

Nor is it the – allies tell me there is no chance of that.

Healey is a serious figure respected by both his Labour colleagues and military top brass.

Until noon today he was also considered one of Starmer’s most loyal supporters who had no truck with ‘s bid for No10.

It is why his devastating departure will crash through Downing Street like one of those laser-guided missiles they are refusing to pay for.

Readers will wonder why a vulnerable PM – who is clinging onto by his fingernails – would risk one of his top ministers walking out the door.

Surely it would have been politically safer – not to mention literally safer – to simply stump up the cash required rather than scrimp?

The suggestion in Healey’s letter is that Starmer was simply too weak to pull rank over other ministers.

One particularly telling line says: “You have been unable, and the Treasury has been unwilling, to commit the resources that the nation needs to defend the country at this time of rising threats.”

In other words, Starmer does not command the authority to demand results from his own Cabinet even for something so important as our nation’s defence.

And all in the context of an ever-growing bill that ministers are too timid to touch.

Given the gravity of it all, this could be the most consequential Cabinet resignation in recent memory.

John Healey's Resignation Letter in Full

DEAR Keir,
This is a letter I never expected to write, and I do so now with great regret and reluctance. I am proud of what we have done in less than two years as a Labour Government. We’ve stepped up to lead internationally for Ukraine with the Coalition of the Willing and Ukraine Defence Contact Group, established Britain as a leading voice for Europe in NATO, raised defence investment to 2.5% of GDP three years earlier than anyone expected, launched the deepest defence reforms in 50 years, won the biggest UK defence export deals for decades, published a first-of-its-kind Strategic Defence Review, gave our Armed Forces the biggest pay rise in nearly 20 years, boosted military morale, fixed over 1,200 of the worst forces family homes, reset relations with European allies and signed major defence agreements with Germany, Norway and France.
You have led this as PM, earning wide respect at home and abroad. Like me, I know you are exceptionally proud of our Forces and all of those who work in UK Defence.
We came into government, recognising Britain faced a new era of threat which demanded a new era for defence. The SDR we jointly commissioned set the 10-year vision to transform our Armed Forces, strengthen alliances, invest in the technology that is changing warfare and back British industry to make defence an engine for growth.
This new era for defence required further investment through the Defence Investment Plan. The excellent and extensive cross-government work that completed in January – overseen by you, me and the Chancellor – confirmed the scale of the challenge and the rising demands on defence.
Since then, you have been unable, and the Treasury has been unwilling, to commit the resources that the nation needs to defend the country at this time of rising threats.
Since then, the demands on defence have increased still further, as have the UK commitments you have rightly made to allies. Conflict in the Middle East, with the UK now leading the multinational Strait of Hormuz military mission; High North security, with the UK now leading NATO’s Arctic Sentry mission; increased Russian activity towards the UK and NATO nations and increased attacks in Ukraine, with the Paris Agreement confirming a British deployment to Ukraine after a ceasefire.
We have worked to secure a Defence Investment Plan that does two things. First, deal with the increasing operational demands on defence now and step up the SDR actions to meet the increasing threat. Second, set a clear path to meet the new NATO commitment you agreed to spend 3.5% of GDP in 2035 through the next Spending Review.
As we have regularly discussed, I am certain that a headmark date for 3% of GDP on defence in 2030 is what Britain must set. This commitment would have strong cross-party support. Other European allies are stepping up in this way.
I know how hard you have worked to get to this point. And in funding the DIP, I fully recognise the strain this places on colleagues in other Departments, both now as you have required spending switched into defence and in the future. I am very grateful to those colleagues who have supported this, and I appreciate how difficult their choices will have been.
As I’ve outlined to you, there are credible ways of meeting the mid-term funding challenges, working multi-nationally and as other European nations are doing, to allow us to protect our ability to deliver the missions of our Labour Government.
However, your DIP financial settlement – which I was first given in full on Monday afternoon this week – falls well short of what is required for defence and the country at this dangerous time. The extra support is backloaded when the pressure of operations and imperative to speed up readiness to fight is in the first two years and it rises to just 2.68% of GDP in 2030, when we will reach 2.6% next year with the investment we are already making.
You spelled out the threats last week: “it is our intelligence assessment, and the assessment of other countries in NATO, that there could be an attack by Russia on NATO as soon as 2030.”
You know what defence needs. You made the argument for this powerfully in your speech at the Munich Security Conference back in February. Without a DIP that meets the moment in this way, I am being forced to make decisions that would reduce the readiness of our Forces and increase the risk to personnel on operations, and could make the country less safe.
After explaining to you that I would not be able to accept a DIP settlement that does not give our Forces the resources they need, I am now left with no other option than to submit my resignation as your Defence Secretary.
I wish you all continuing strength in the exceptional challenges you face as Prime Minister. As always, our Labour Government will continue to have my fullest support.

A letter from Rt Hon John Healey MP to the Prime Minister, detailing his achievements as Defence Secretary and expressing regret over the government's failure to commit resources for defence.Mr Healey is the fourth Cabinet minister to leave Sir Keir’s Government Credit: X/JohnHealey_MP

Mr Healey is the fourth Cabinet minister to leave Sir Keir’s Government since coming to power and the second to resign over policy differences.

The ex-Cabinet minister warned he was being forced to make decisions that could leave troops at greater risk and “make the country less safe”.

It comes amid a bitter row over Labour’s Defence Investment Plan and how much ministers were prepared to put behind it.

Mr Healey said the package handed to him this week “falls well short” of what Britain’s military needs as threats from Russia continue to grow.

In a direct challenge to the PM and Chancellor Rachel Reeves, he wrote: “You have been unable, and the Treasury has been unwilling, to commit the resources that the nation needs to defend the country at this time of rising threats.”

Mr Healey added: “Without a DIP that meets the moment in this way, I am being forced to make decisions that would reduce the readiness of our Forces and increase the risk to personnel on operations, and could make the country less safe.”

The Labour heavyweight also pointed to Sir Keir’s own warning that could be in a position to attack by 2030.

He told the PM: “You know what defence needs.”

A flurry of MPs took to social media to react to Mr Healey’s resignation.

Labour MP Jim McMahon said: “You were an outstanding Defence Secretary John, and principled from beginning to end.”

Former Tory home secretary also paid tribute to the former Cabinet Minister.

He said: “I have always respected .

“He clearly takes defence of the realm and defence of our interests more seriously than either Keir Starmer or .”