The PM is in a hot mess - and I've never seen anything like it

Less than a year ago in Downing Street, the bunting was out, and Keir Starmer was walking into No 10 to a chorus of cheers after winning a landslide victory.

Now there's such a rebellion from his own MPs, he's being forced to climb down on his welfare reforms.

PM set to make serious concessions - politics latest

For a prime minister to face such a challenge so early in his premiership, with such a big majority, is simply unprecedented.

It is a humiliating blow to his authority from a parliamentary party that has felt ignored by Downing Street.

How has this happened?

The PM's entire focus for the past 12 days has been on international diplomacy.

He's gone from the G7 in Canada, trying to deal with Trump, trade deals, de-escalation; then Israel-Iran, he was at Chequers trying to deal with that crisis; and then he was straight to NATO.

You could forgive him for being pretty angry that those who should have been managing the shop back home have ended up in such an enormous blow-up with MPs. A PM needs to be able to trust his team when he's dealing with international crisis.

As I understand it, a month ago up to 140 MPs signed a private letter to the whips warning they would not accept the welfare reforms.

The whips told No 10 - and No 10 it seems stuck their fingers in their ears and didn't pay attention to it.

But this is really draining on the PM's authority. Ultimately, he carries the can.

What happens next?

As I understand it, he's now looking at serious concessions in order to get his welfare bill passed on Tuesday.

No 10 are considering whether they drop the PIP changes for existing claimants, and the health element of universal credit for existing claimants too.

Speaking to me on the Electoral Dysfunction podcast, Labour peer and ex-minister Harriet Harman said she expects concessions to be enough to appease enough of the rebels.

It will leave the chancellor needing to look somewhere else to make billions of pounds of savings.

Read more:What are the PM's welfare reforms?

It's a hot mess, and it was avoidable. It has left very bad blood between the parliamentary party and No 10 and No 11. There's a lot of ire directed at Rachel Reeves at the moment too.

For a PM to be facing such an overt challenge to his authority with a working majority of 165, less than a year into his leadership, having to U-turn because he's facing defeat?

I've never seen anything like it.