The defence secretary has resigned over the government’s military spending plans, in another major blow for Keir Starmer. In a scathing letter to the prime minister, John Healey said the long-awaited defence investment plan ‘falls well short of what is required for defence’ and that he would have to take decisions that ‘could make Britain less safe’. Nosheen Iqbal speaks to policy editor Kiran Stacey

During Wednesday’s prime minister’s questions, the defence secretary was standing at the other end of the Commons, away from other cabinet members on the government frontbench. His expression gave nothing away as Keir Starmer and Kemi Badenoch blamed one another for spending too much on welfare and not enough on defence. In hindsight, he was possibly thinking “to hell with both of them”. Most defence secretaries go native sooner or later, imagining themselves to be embedded officers serving on the frontline. Tory Ben Wallace appeared to hate most of his cabinet colleagues by the time he resigned in 2023.

Less than 24 hours after PMQs, Healey had also resigned, his departure being all the more powerful for being so unexpected. This exit seemed to come out of a clear blue sky. There had been no briefings to the media in the preceding days. No threats to stand down if his demands were not met. All the arguments had taken place behind closed doors. A determination to do the right thing throughout.

His resignation letter to Starmer was polite but deadly. Amid the standard pleasantries in which he said what an honour it had been to do the job and listing the Labour government’s achievements came the killer lines. Rachel Reeves had failed in her duty to give the armed forces the bare minimum to safeguard the defence of the country. And the prime minister had been too weak to overrule his chancellor. Keir had always talked the talk about the security of the country being his prime priority but when push came to shove he hadn’t walked the walk. So Healey had been left with no choice but to act according to his conscience.

For Starmer, this was devastating. The wrong resignation at the worst possible time. He could brush off the departure of a health secretary. Wes had just been Wes. Always on manoeuvres. No one would really miss him. But Healey was in a different league. There wasn’t anyone who thought he had resigned as part of a self-promotion strategy. This was a resignation of a man who felt he had been left with no other choice.

The defence investment plan had been meant to be Starmer’s legacy. Not that anyone was allowed to mention the L word. Within earshot of the prime minister, everyone in No 10 is obliged to act as if he will lead Labour into the next election and a dreamland beyond. But Keir must know the game is almost up. Surely his family have had a quiet word. The drum beats from Makerfield are getting ever louder. This time next week Andy Burnham is odds-on to be an MP. After that it’s only a matter of when.

Now it looks like the Dip will struggle to see the light of day before Makerfield. Far from positioning himself as the prime minister who ringfenced the security of the country, Keir might end up being remembered as the man who put it at risk. By mid-afternoon on Wednesday, the wagons were circling. Kemi Badenoch and other opposition MPs were wasting no time in putting the boot in. Praising Healey to the heights – no flattery is more insincere than a politician pursuing their own advantage – while accusing Starmer of epic levels of betrayal. No one will care or remember it was the Tories who did most to hollow out defence spending.

The danger was not just coming from just the opposition. Tan Dhesi, the Labour chair of the defence select committee, spoke out against the apparent shortfalls in the Dip budget. As did the junior defence minister Al Carns. He described the Dip as not fit for purpose and Healey as a man who had given serious service.

Starmer appeared trapped. Unless he could squeeze at least £15bn more out of the chancellor, he would struggle to appoint a new defence secretary. Because who would want a job the previous incumbent had said was untenable from a lame duck prime minister? And Keir would be equally damned if Reeves did find the money. Because why had it taken the resignation of one of his most able ministers to do it? He was screwed either way.

Still, at least Healey’s departure was a distraction from the riots in Belfast that had spilled over into a second night on Wednesday with 12 police officers injured in the violence. No one seems to be listening to the wishes of Stephen Ogilvie’s parents as they appeal for calm. Then no one listened to Mark Nowak either. People now think they have a right to act on their anger. No one in Northern Ireland batted an eyelid when dozens of white women were killed by white men. Not worth getting out of bed for. But when a black man attacks a white man …

At times like this, the world seems to be tilting ever further to the right. Kemi tries to make the Tories ever more like Reform. First by promising to abolish the public sector equality duty and then telling the Spectator she would be happy to put Nigel Farage into No 10.

Reform meanwhile become ever more like Restore with Nige calling for “pure, cold rage” and then feigning amazement when he gets it. Restore now spend their time chasing Tommy Robinson as he makes helpful suggestions about areas with immigrant populations where it might be fun to riot. And Robinson has the endorsement of Elon Musk. Musk now has so many personalities, he isn’t quite sure who he is at any one time so sends avatars of himself out to chase the others to the extreme right. All the time sitting in his bedroom by himself as he becomes the world’s first trillionaire. Maybe you can call this following the money.

It was left to the Northern Ireland secretary, Hilary Benn, to try to make some kind of sense of this on the morning media round. Was the violence racially motivated, he was asked on the Today programme. Er, hello? When a mob of white people attack black people, what else are you going to call it.

He then tried to dial things down. “This isn’t who the people of Northern Ireland are,” he insisted. Except it clearly is who some of the people of Northern Ireland are. Because they are doing it. The attacks are happening. And older members of the country can clearly remember a time when violence was an almost daily occurrence with the police in the frontline. Most had hoped that was a thing of the past. But for some it has moved on from religion to race.