Yesterday, reviewing Jeremy Corbyn’s conference speech, I wrote the following:

‘…he chose to shoot back against Trident, despite the unions’ warnings and reports that yesterday the Labour conference (perhaps unawares) voted in support of Trident renewal. That decision was, as Sir Humphrey might say, courageous – had it come within a speech which established his genius and his dominance then he would have got away with it. Instead, it came within a not very interesting ramble which suffered from at least one false finish – and as such it simply guarantees another bout of fighting with his internal critics.’

I didn’t necessarily expect it to happen in under 24 hours, but it has.

Not content with committing to give up the nuclear deterrent (like Ukraine did in the 1990s – how did that work out?), today he doubled down and declared on the Today Programme that if elected he would never under any circumstances push the nuclear button. That presumably includes circumstances in which doing so could protect the United Kingdom, which is less than reassuring. It also means that if elected he would destroy the deterrent potential of Trident even if his Party’s policy was to renew it – a hugely foolish thing to do.

The whole concept of nuclear weapons, and the relative peace which they have brought, is that there must at minimum be uncertainty over whether a leader will use them – destroy the uncertainty and you risk the peace. We can only hope that Vladimir Putin was off in the Urals doing a shirtless photoshoot on the back of a bear, or punching an elk in the face, and not listening to Radio 4 this morning.

As predicted, the response has been consternation within Labour’s ranks. Various members of the Shadow Cabinet specifically sought assurances on this issue before agreeing to serve under Corbyn – and they aren’t happy.

Here’s Maria Eagle, the Shadow Defence Secretary:

“I think it undermines to some degree our attempts to try and get a policy process going. As far as I’m concerned we start from the policy we have…I don’t think that, a potential Prime Minister answering that question like that, in the way in which he did, is helpful.”

And Angela Eagle, Shadow Business Secretary (and the person who will stand in for Corbyn at PMQs):

“If you’ve got nuclear weapons systems you’ve got to be prepared to use them.”

And Hilary Benn, the Shadow Foreign Secretary:

“I think a British prime minister has to have that option and the whole purpose of the deterrent of course is it is trying to deter a potential enemy because they’re not sure what you’re going to do and that puts them off.”

Meanwhile Andy Burnham, the Shadow Home Secretary, seemed to imply that collective cabinet responsibility is already dead in the Labour Party:

“Everybody’s got to speak for themself and Jeremy has done that.”

Corbyn’s response is to promise “a discussion” – not exactly a firm answer to criticism that he is endangering the nation and alienating voters. When your Shadow Defence, Foreign and Home Secretaries and your PMQs stand-in all disagree with you on an issue you feel to be fundamental, how do you come back from that? When the electorate already thinks you are both incapable and divided, publicly demonstrating both is not a wise step.

I’d fully expect the Conservatives to push on this sore spot next week in Manchester – and potentially to try to ambush Angela Eagle on the topic at her first PMQs. The Opposition front bench doesn’t look like a very comfortable place to be right now.