Chris Mason: Healey's resignation is a devastating critique of Starmer's government

Two words leap out of John Healey's resignation letter and they amount to a devastating – and recurring – critique of Sir Keir Starmer's government.

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

Healey is the sixth government minister to resign since Labour's disastrous showing in last month's elections.

He is the fourth full cabinet minister to resign from Sir Keir's government after Louise Haigh, Angela Rayner and Wes Streeting .

Healey's resignation as defence secretary comes on the day so many in Westminster expected would be when the government's long anticipated Defence Investment Plan was published.

It was becoming abundantly clear it wasn't going to see the light of day yet, because of rows within government about how to pay for it.

And this just a week before Healey was due to attend a Nato defence ministers meeting in Brussels - and a week before the crucial Makerfield by-election, when Andy Burnham could return to parliament and take on the prime minister.

Little wonder there was a desire from Sir Keir to get on with doing big stuff before then, if at all possible.