So now we know Jeremy Corbyn will be on the ballot to defend his position as Leader.

By an 18-14 majority the NEC ducked treating him equally to other candidates and requiring him to be nominated by 20 per cent of the PLP and EPLP. This is daft – how can anyone lead a party if they have support from fewer than 20 per cent of its parliamentarians? – but at least ensures that if he is beaten no one can question the process and the “mandate” and legitimacy of the winner.

However, at the same meeting the NEC closed some of the loopholes that turned last year’s election from a battle for hearts and minds of actual long-serving members into a lop-sided stacking exercise, won by the team with the biggest email lists. The notorious £3 Registered Supporters scheme will now cost £25 and only be open for three days between 18 and 20 July. There is a six month freeze date meaning to vote as a full member you will need to have joined before February (presumably newer members can pay the £25 to vote as Registered Supporters).

I am not sure what the point is in Jeremy running for re-election.

If he wins he will still be in the same position:

With an 18 per cent rating on whether people want him to be PM compared to 62 per cent for Theresa May and behind “don’t know” on 20 per cent

8 per cent behind the Tories in the opinion polls

Without the confidence of over 80 per cent of the PLP

With a frontbench so full of holes Labour cannot physically transact the day-to-day business of parliamentary opposition

With the Soft Left so alienated they are actually leading the charge against him

With public knowledge of the low esteem his closest colleagues have for his performance

With many of the young people who he inspired in 2015 deeply disillusioned that he let them down during the referendum campaign

With the activists and councillors who are Labour’s campaigning backbone in open rebellion

None of this will be changed if Corbyn is re-elected, however wide the margin. MPs are not going to go crawling back to him saying they made a mistake. They will challenge him again and again as his failings and the untenability of his position become more and more apparent, until eventually he is defeated.

If he is re-elected and May calls a snap General Election this autumn Corbyn will go down in history as someone who chose to lead Labour to devastating defeat – probably including losing seats deep into our industrial heartlands – out of personal stubbornness and factional malice, rather than admit he is simply not up to the job of leadership and has political views that are anathema to most British voters.

If he is re-elected there will not be a split.

Members may quit in disgust. People may choose to drop out of political activity to do something more enjoyable. This will be understandable but ultimately self-defeating. It is what the Hard Left want – to make Labour such a miserable and vicious place that only they feel comfortable in it. Letting them have their way is just going to delay Labour’s eventual recovery.

But there won’t be a split along 1981 SDP lines with MPs founding a new party.

The lesson of 1981 was that Owen, Jenkins, Williams and Rodgers achieved nothing except personal ignominy whilst people with similar politics like Healey and Hattersley and Smith who stayed and fought got to see their party won back and winning elections.

We need fighters not quitters. This is tough but we know from 1997 that the prize – an electable Labour Party with everything it can do for working people – is more than worth the struggle.

The same goes for any future Scargills who want to try setting up a new Socialist Labour Party if Corbyn loses.

Anyone, right or left, who forms a breakaway party will find it near impossible to make an electoral breakthrough due to the First-Past-the-Post voting system. All they will do is split the centre-left vote and help the Tories, and harm their own side within Labour by tarnishing the stayers as potential leavers.

Corbyn can be beaten. I am confident that there will be only one moderate candidate, making this a binary choice. Corbyn’s character and politics are a lot better understood than they were in 2015 by people in the centre and soft left of the party who were prepared to give him a chance. Pro-Europeans have been deeply alienated by his role in the referendum. His sectarianism and that of Momentum has created an unprecedentedly broad alliance against him, a coalition of everyone who wants to save Labour as an electoral force which transcends right and left.

If he cannot be beaten this summer he will be beaten in 2017 or 2018.