Political warfare is full of sacrifices, some noble, some pointless. John Healey went over the top soon after midday. Fellow officers nearby said he did so with remarkable sangfroid. A final letter. A last, defiant Woodbine. Disinclined to obey orders to surrender to the hated Treasury, Capt Healey of the Rawmarsh and Conisborough Fusiliers then rose from his trench and charged at the enemy, bayonet fixed.

His letter of resignation blamed both Sir Keir Starmer (‘unable to commit the resources needed to defend the country’) and Rachel Reeves (‘unwilling’). Comrades said it was magnificent. Poor blighter didn’t stand a chance yet he fell in a blaze of glory. His attack probably won’t alter much for Sir Keir, who already looks a goner, but it will not have done Ms Reeves any good.

She has been prancing around the place depicting herself as an agent of stability. That brazen falsehood just blew up, spectacularly. How can any relaunch of the government succeed with her still in situ? ‘Unwilling’ to give our armed forces what they need for the very minimum of national security? That is a deadly epitaph for a chancellor.

This was the best Defence Secretary resignation since Michael Heseltine’s and it was all the more dramatic for coming from a politician who for years has been the epitome of level-headedness. You might think ‘level-headed’ a synonym for dullness but John Healey was better than that. Although you would never call him exciting he had an ability, rare in the Cabinet, to sound grown-up, patriotic and non-partisan. At the weekly session of PMQs he almost never sat on the government front bench. Instead he would stand at ‘the bar of the House’, which is the central entrance area opposite the Speaker’s chair. He abjured the silly cheering and yabooery. He would just cross his arms and listen to the exchanges, raising little more than one pale eyebrow.

The parliamentary day had already been peculiar, simply by dint of what was not happening. From the end of last week Westminster was told this was the day the Defence Investment Plan would be published. It was going to allow Sir Keir to have a ‘legacy moment’ before Andy Burnham’s expected win in the Makerfield by-election next week. The days passed and there came no official confirmation that Thursday would indeed be the moment. Reporters who telephoned 10 Downing Street to ask about the Defence Investment Plan met with slightly hysterical whinnies.

The Plan had become a damaging political joke. For almost a year ministers promised it was coming ‘soon’, ‘shortly’, ‘in due course’ and so forth. We were Waiting for Godot. The Plan was going to be published last autumn. Nothing happened. Opposition MPs and pro-military Labour MPs such as Tan Singh (Slough) of the defence committee pressed and pressed. At PMQs on Wednesday Sir Keir actually chuckled when asked about the Plan, as if accepting how absurd the delay had become. Beside him Ms Reeves looked indignant at the mockery.

Then came a new rumour that the Plan would be published on Friday, in Swindon. Mr Speaker erupted. He expected such matters to be announced in the Commons, not halfway down the M4.

As the bugler flexes his lips to play the Last Post, how, therefore, should we categorise this lonely sacrifice? Noble? Pointless? Both of those things? It certainly looks noble as it was on a matter of principle. The timing may also have been astute. Aged 66, Mr Healey has made himself a bigger character just when it may be no bad thing to look fresh. Any incoming PM will not be able to write him off as a Starmerite time server.

Beyond such career considerations, will it achieve anything? That is up to Labour backbenchers. It is their obstinate adhesion to high welfare spending that is at the root of this problem. Not until they see the dottiness of putting welfarism over national security can their party recover.