Alastair Campbell

Breaking news, Defence Secretary John Healey resigned from the Cabinet.

Worse for Keir Starmer, he did so at a time when the Prime Minister is facing a possible leadership challenge in the coming weeks or months, with the likeliest challenger, Andy Burnham, exactly one week away now from the by-election that may see his return to Parliament.

And

Perhaps most devastating of all, John Healy makes clear in his resignation letter that leadership is the issue.

This line, which I suspect hit Keir Starmer quite hard.

You have been unable, writes John Healy, and the Treasury has been unwilling to commit the resources that the nation needs to defend the country.

So he's got Rachel Reeves as well as Keir Starmer in his sights, and he's going down fighting, I guess.

The issue is defence spending, more particularly what's known as the Defence Investment Plan, which he thought had been broadly agreed some time ago, which has been sitting on the Prime Minister's desk amid some very, very tough negotiations.

So we've got a few immediate questions.

Who replaces him?

When does the defence investment plan get published?

And Lindsay Hoyle, the parliamentary speaker, exploded today at the idea it might be tomorrow when most MPs are away.

And I guess it also begs the question, where does this leave Keir Starmer on the authority front?

So, Rory, where would you like to start with what is quite big news?

Oh, it is pretty grim.

When you look at the numbers of size of armed forces, equipment and kit that is available to us, this is why the defence spending issue is so fraught.

Because the truth is, everybody accepts that we need to spend more defence, but other ministers have fought very hard to protect their own budgets.

And John Healy's clearly decided, this is not enough.

I can't carry on being the person speaking up for strong defence if I don't believe that we're actually providing it.

Because that's why that line was so devastating.