Labour’s descent into self-destructive warfare has entered a new phase after the party’s executive ruled that Jeremy Corbyn can stand for re-election as party leader before sparking anger among his supporters by changing the rules as to who can vote in the contest.
The ruling that Mr Corbyn automatically has the right to stand makes it highly likely he will win the leadership contest triggered by Angela Eagle’s announcement that she is standing against him.
And a Corbyn victory will exacerbate the rift between Labour MPs, three-quarters of whom have backed a motion of no confidence in Mr Corbyn, and the mostly young activists around the country for whom Corbyn’s election last year has given a new meaning and purpose to politics.
Amid fears of a party split, the meeting of the National Executive Committee also provided a concession to Mr Corbyn's critics - tightening the rules about who can vote in a leadership contest.
Last time it was open to anyone prepared to pay £3 - and it was the £3 supporters, more than the paid up party members, who gave Jeremy Corbyn his swingeing victory.
This time, supporters will have to re-register and pay £25. And the thousand of new recruits who have joined the party since the referendum will have to pay that fee if they want to vote, because the executive has ruled only those who have been party members for at least six months will have an automatic right to vote.
The move has been criticised by Mr Corbyn's supporters.
James Schneider, a spokesman for the Corbyn-backing Momentum organisation, said the January 12 cut-off for securing a vote in the leadership poll was "not fair".
Mr Schneider told the BBC: "We've seen since the Brexit vote probably the largest surge in political party membership in this country's history, with almost 130,000 people joining the Labour Party and a great number of those joined on the basis that they would be able to vote in a future leadership election."
A 38Degrees petition set up immediately after decision was announced calling for a reversal has already gathered over 2,000 signatures.
The petition, which was set up by Tim Longson, said: "We believe that as this will disqualify up to 20% of the whole Labour party membership (around 100,000 members), and that this is unacceptable and misrepresentational (sic) of the democratic Labour membership will.
"Failure to meet with this very reasonable request of such a huge body of members may possibly suggest that the NEC leadership is, in fact, deliberately trying to block the additional votes of the these 20%, indicating some bias.
"Further, in light of the fact that has been strongly suggested that the vast majority of these new full Labour party members are backing Jeremy Corbyn, and would vote for an NEC team who would also lean that way, it would suggest this bias is directed against Jeremy Corbyn's leadership."
Mr Corbyn has said he is "delighted" by the result, and urged his critics to unite "to offer an alternative to this Tory government".
A former political advisor to Tony Blair, Ian McTernan, said the victory for Mr Corbyn had set the party on course for a split and was "the end of the Labour party, nothing more or less than that".
He said the Labour has ben been "stabbed in the heart and killed by the Labour National Executive Committee."
Mr Corbyn’s backers had feared that the executive would force him to find 50 Labour MPs or MEPs – a fifth of the parliamentary party – prepared to sign his nomination papers before his name could go on to the ballot paper. The leader’s support among fellow MPs has hit such a low point that it is unlikely that he would be able to find that many supporters in the Commons.
Labour Party members and supporters who gave Mr Corbyn an overwhelming mandate nine months ago will now get a second chance to vote for him.
But Ms Eagle, one of more than 60 members of Labour’s front bench who resigned in protest at Mr Corbyn’s leadership, still thinks she has a chance. She said: "I'm glad Labour's NEC has come to a decision. I welcome the contest ahead. And I am determined to win it."
A Labour MP supporting Angela Eagle told The Independent "it's not impossible" that she could defeat Corbyn. "He only just won 50 per cent of the full members last time."
Owen Smith also threw his hat into the ring on Wednesday morning.
If Corbyn did win, the MP said, there was no question of most MPs constructing an opposition around him. The MP said that the anti-Corbyn majority of MPs would not split to set up their own parliamentary leadership. "I don't think anyone is thinking of that."
The MP did not rule out another attempt at the leadership next year but said: "If Jeremy is the leader we would be totally vulnerable to a general election. If you were Theresa May, we'd be completely on our backs, why wouldn't you?"
During an interview on BBC’s Newsnight, Ms Eagle refused to say whether a Corbyn victory would spell the end of Labour as we know it, saying she was "not going to speculate about what will happen if I lose".
"I think it is important that we take the broad base of the Labour party with us," she said. "We need to be an effective Labour party going forwards."
The anger which the dispute has generated has threatened to turn to violence far beyond the realms of simple party politics.
A brick thrown through the window of Angela Eagle's constituency party office in Wallasey is assumed to have been a political act – though Mr Corbyn has condemned all such actions, whether by his supporters or his political opponents.
A meeting that Ms Eagle was due to address in a hotel in Luton had to be moved to a new venue at short notice after the hotel received threats. An obscene message was left on the phone in her Commons office. Her angela4leader Facebook page had been deluged with messages taunting her and showing support for Jeremy Corbyn.
And dozens of Mr Corbyn’s supporters had turned up outside Labour’s Westminster headquarters to show support as the executive met to decide on the issue which threatened to cut Mr Corbyn’s leadership short without so much as a vote.
It all started because the Labour Party rule book specifies that when a sitting leader is challenged, any challenger must secure the nominations of at least one fifth of all Labour MPs and MEPs, a hurdle Angela Eagle crossed without difficulty before launching her bid for the leadership on Monday.
The executive was presented with conflicting legal advice on whether the same rule applies to a sitting leader. Mr Corbyn adamantly claimed that he had an automatic right to stand and should not be required to seek any nominations.
Two hours into a tense afternoon it appeared that the mood might be swinging against Mr Corbyn, when the executive decided by 17 votes to 15 to hold a secret ballot. The Labour leader was asked to leave the room while his case was discussed. At first he refused, but then agreed to wait in another room in the same building. He later went back into the meeting and took part in the vote.
The executive had also been sent a letter from a solicitors’ firm, Howe & Co., complaining that the meeting had been called at too short notice and putting the executive on “the clearest notice” that if they did not allow Mr Corbyn’s name to go on the ballot automatically, they would face an injunction in a high court to get their decision reversed.
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