As Roy Castle did not sing at the end of each episode of Record Breakers: “Deselection, that’s what you need.”

If Labour is to split, that will be the trigger.

Many are asking how much more can the so-called moderates in the party put up with – the likes of Chuka Umunna, Liz Kendall and Rachel Reeves have largely sat tight since the general election. Albeit some more tight than others. The result last June showed that Corbyn could win. It didn’t prove that he had it in him to actually become Prime Minister but he is not the dead loss with the public many feared following two leadership victories powered largely by zealots.

The Labour natives were getting restless even before the party was engulfed by antisemitism accusations yet again.

Partly because they are bored (never underestimate the power of boredom in politics). Through 2015 and 2016 they had the distraction of gossiping, plotting and generally undermining the leader. In 2017 that stopped.

Also because the party machine has been comprehensively captured by the Labour left. Jennie Formby’s installation as the party’s general secretary essentially the final part of that project.

Aside from the personnel there’s the policy. Backbenchers that have buttoned their lips as Brexit has unfolded and put their faith in Keir Starmer seem to have been rewarded as the party slowly drifts from not really having a policy to supporting remaining in a customs union and inevitably closer to a textbook soft Brexit. Owen Smith, who cackhandedly challenged Corbyn in 2016 and then kowtowed his way to the post of shadow Northern Ireland secretary, spoke out too soon and got sacked for his trouble.

But Corbyn’s response to the Salisbury poisoning proved too much with his own backbenchers condemning is equivocation. Big beasts like Yvette Cooper, Pat McFadden and Chris Leslie were stirred. The sort of people who can raise a following.

That has been followed in short order by a tide of accusations of anti-semitism. The latest raised by Luciana Berger last week when it seemed Corbyn had condoned an obviously anti-semitic mural in a Facebook comment. It may have happened a few years ago but it was an open and shut case of, at the very best, crass naivety.

But those expecting the weekend hoo ha to be the last straw will be disappointed.

For apparently principled politicians who genuinely and honestly believe either Jeremy Corbyn cannot be Prime Minister or if circumstances were to put him in Number 10 it would be a disaster appear to just suck up humiliation after humiliation.

Some might say that’s because there’s unlikely to be an election soon and they are happy to take the salary and the perks for another four years. There may be something to that.

Others have an emotional attachment to the Labour party and they feel they can no more walk away from it than they can turn their back on their own family.

But a deselection would change all that. The emotional equation would be undone and their job prospects in parliament would shrivel.

One senior moderate explained how it would work. A single deselection would see that person resign, force a by-election and stand as an independent. When other moderates turned out to canvass for their former colleague they’d be in breach of party rules that forbid campaigning for anyone other than the official. Labour candidate. Expulsion would surely follow leading to a large group of independents or a ton of by-elections. Or both.

If this involves just a handful of the usual suspects it would be unimportant. But those involved are talking about serious numbers – As many as 150 Labour moderates effectively quitting in the face of a single deselection.

Of course that may be little more than fighting talk aimed at scaring Corbyn and his Momentum chums away from any policy of mandatory reselection.

But those involved insist it’s for real. At the very least it shows Corbynsceptics are giving practical thought to their exit from the Labour party and what happens next.

If the numbers are right, it’s a high stakes game. The moderates are having to resort to desperate measures as their bargaining power seeps away. Soon they’ll only be left with the option to hit the nuclear button. Who among them is brave enough, or foolish enough, to press it?