The wonder of John McDonnell’s speech this morning was not so much anything he said, but the fact that anyone in Labour is still standing and saying anything at all. Standing Up Not Standing By was the apt slogan on his podium.

Never mind the content, business as usual was McDonnell’s message. Quite who the advertised “business” people were assembled at the Royal Festival Hall isn’t plain, since most probably eye him as likely to hang them from the nearest lamppost, despite his reassurances that the financial industry needs protecting for everyone’s sake, not just the fat cats. To judge by the cheers he received, most were Corbyn/McDonnell activists.

Doing his very good imitation of a bank manager, McDonnell said, “We will get through this period of uncertainty”. It was a perfectly plausible speech, but with the same cake-and-eat-it problem that everyone is struggling with – yes we’ll stay in the single market; no we won’t accept free movement. If Corbyn hadn’t so forcefully emphasised his belief in free movement on the eve of the poll, he might not have lost the 27% of core working class Labour voters who now say they won’t be voting Labour again. It’s that cataclysm facing Labour, in what might be an imminent election, that precipitated the great rebellion against their leader.

Expecting a leadership challenge, the membership wars are on, as both sides dash to recruit. An astounding 60,000 have joined in a week, bringing the total above 440,000, beyond its 1997 peak – extraordinary for a party on the verge of utter disintegration. Under the insane rules, £3 membership, suspended in normal times, starts again with a leadership contest. But ordinary membership is cheap as chips at £3.92 a month, and can be cancelled any time.

Who are these new members? The party says they split 50/50 on whether to support Corbyn or to find a new leader, according to comments people leave as they join up, with the new Saving Labour site recruiting people to urge Corbyn to step down. How party members feel will determine the fate and survival of Labour, if it comes to a contest. If he’s re-elected, no one knows what splits will follow.

A YouGov poll of Labour members in the Times today, taken in the last week, compares the mood with a poll in May, pre-referendum. Corbyn only just still has the edge, but support is tumbling from an approval rating of +45, to just +3.

If Jeremy Corbyn goes with dignity, that leaves Labour free to hold a genuine leadership contest

Angela Eagle was ready to challenge yesterday and trigger a leadership contest, but she has held fire on the advice of Tom Watson and others, who still hope Corbyn might step down gracefully. After a savage week, where he has been battered and insulted by just about his entire party, with 80% of MPs, and most MEPs and former leaders telling him to go, how much more can a man take? He draws deep ideological strength from those grassroots rallies – because in his revolutionary Bennite ideas, extra-parliamentary action counts for more than elected MPs.

He has the weekend to consider the meaning of life. Might his family protect him from what can only be worse to come? Some say he’s a prisoner to consiglieri who won’t leave him alone to ponder the joys of his allotment. Seumas Milne, John McDonnell, Diane Abbott and others will screw his courage to the sticking point, because if he steps down, the far left’s astonishing capture of the party will be over. All those wilderness decades of disobeying party leaders, espousing issues obscure to most Labour voters will have been wasted. If he goes, McDonnell could stand – but few think he could raise the 51 nominations from MPs. So they will nail the politically dead Corbyn to his chair, like El Cid.

There are two views as to whether Corbyn really is a nice man – but only the heartless wouldn’t feel pity for these humiliations. The disastrous launch of Shami Chakrabarti’s antisemitism report shows what happens to leaders without support: accident-prone, everything they say is a gaffe. She tried to rescue him from accusations of an apparent comparison of Israel to Islamic State, but a Jewish MP leaving in tears after being bellowed at by a Corbynite is all anyone will remember of Labour and Jewishness.

These could be the end days of Labour. Expect a challenge to Corbyn shortly, but there are wrangles as to who should do it: splitting the anti-Corbyn vote would be suicidal. Eagle has most support – soft-left, close to the unions, level headed, an experienced safe pair of hands. Owen Smith takes a slightly further left stance, but some say it can’t be someone Welsh, and he’s unknown. Watson is the key player, a wise bargainer and as deputy leader the one with a direct mandate elected by the party membership: he still hopes that Corbyn can be talked down off his miserable throne of thorns before Monday.

If he goes with dignity, that leaves Labour free to hold a genuine leadership contest between different views of the future. If he has to be challenged, debate is limited as just one contender comes forward – a loss at a time like this.

As Gaby Hinsliff wrote today, the volume and vitriol of abuse from Corbyn supporters against MPs and all opponents is phenomenal. Look no further than the comments below her column – or no doubt those following this. After one tweet yesterday about Saving Labour, I had “Blairite scum” and “neoliberal fascist” abuse by the bucketload. The Labour challenger will need the hide of a rhinoceros – and Angela Eagle is battle-hardened. This is the endgame, the battle to the last.