On the surface, it was another byzantine Labour party argument about rule changes. But the row about changes to the National Executive Committee that broke into the open at the party’s conference in Liverpool on Tuesday is the latest battle for the future direction of the party. And this is one that Corbyn lost, just three days on from being re-elected leader.
Despite the best efforts of his team, the Labour leader was outmanoeuvred in a tussle that has run throughout the conference, as he attempted to ensure he remained in control of his own party's executive committee.
On Tuesday afternoon the delegates in Liverpool approved a much-disputed set of rule changes that could give the anti-Corbyn leaders of Scottish and Welsh Labour a dedicated seat on the organisation. The vote also ensures the anti-Corbyn faction are able to maintain a power base within the party, even though other pro-Corbyn NEC members are due to join next week.
The NEC, the body that decides Labour's rules and structure, and which includes representatives from across the Labour movement from local parties to appointees of the leader and trade union officials, is currently finely balanced between pro- and anti-Corbyn forces.
It was the NEC that chose to block new members from voting in this summer's leadership election, raised the price of becoming a registered supporter to £25, and was at the heart of the dispute over whether Corbyn would automatically appear on the ballot.
Tuesday's rule changes mean that balance of power has changed. Essentially, the gains made by the Corbyn left of the party in recent membership elections are now set to be outweighed by the new arrivals.
The struggle has focused the anger of some Corbyn supporters on Tom Watson. Some of the leader's allies believe his deputy has been the guiding hand behind the scenes in the dispute. They are also fearful that Watson's power base is set to grow again as he hires his own personal team of advisers in the coming days.
Watson received a standing ovation from party activists when he defended the record of the Blair and Brown governments in his conference speech on Tuesday afternoon – but it was less warmly received by Corbyn, who was sitting on the stage.
Watson, the party's self-proclaimed "fixer", gets most of the blame from Corbynites.
Len McCluskey, the pro-Corbyn leader of the Unite trade union – and Watson's former housemate – is one of those who was deeply displeased with the deputy leader's role in the power struggle. When asked by BuzzFeed News whether he was happy with the way Watson had acted, McCluskey replied: "No, no I'm not."
According to one Labour MP: "Even though Tom's trying to keep his fingers off it, everyone knows it's got Tom's fingers all over it."
Still, the brutal political battle has been held out of sight away from the floor of the party conference, with the two factions facing off at unprecedented early morning meetings in Liverpool.
"Having the morning NEC meetings is almost unheard of – they always, without fail, got cancelled every morning," said one former NEC member with experience of previous conferences. In effect it was political trench warfare, with neither side willing to budge.
At the heart of the battle was the NEC's proposal to create two new seats on the 33-strong committee for Welsh Labour and Scottish Labour, both of which currently have anti-Corbyn leaders. Rather than allow Labour delegates attending the party conference in Liverpool to vote directly on the proposal, the idea was combined into a single package of NEC reforms along with several other changes strongly supported by the pro-Corbyn faction.
A source at Unite blamed Watson for the decision to combine the measures into one package, criticising him for "cherry picking" a selection of NEC changes that would be difficult for Corbyn supporters to totally oppose.
Unite had hoped to broker a compromise in which Scottish and Welsh members were allowed to influence the choice of delegates, rather than simply allow the respective leaders to nominate an individual. But this proposal failed to make it into the final package put to the vote – and Unite were forced to drop their opposition in order to get the final package through conference.
The anti-Corbynites were also boosted by the efforts of Labour First, which had worked over the preceding months to maximise the number of centrist party activists elected as conference delegates with voting power.
"Moderates have rightly been organising in elections for conference delegates for this conference for the past year because they know how much is at stake," said one individual involved in that effort.
Some furious Corbyn supporters took the conference floor on Tuesday morning to accuse "parliamentarians who are not accountable to this movement" of "gerrymandering" the party to maintain their power.
"Adding nominated members rather than elected members to the NEC is an anti-democratic attempt by an NEC that’s composed of a significant number of people who’ll be leaving at the end of this week to try and rig the deck afterwards," said delegate Steve Walker.
But it was too late and the package of reforms passed, giving both the Scottish and Welsh parties a spot on the committee with immediate effect. Scottish leader Kezia Dugdale, who has a strained relationship with Corbyn, has said she will nominate herself while Welsh leader Carwyn Jones will phone into tonight's NEC meeting before choosing a nominee.
The wounds of the battle may take some time to deal. After Watson finished addressing conference on Tuesday a Unite source remarked it was "not a very statesmanly speech" and said his comments were a "missed opportunity to embrace the unity the party wants".
But a spokesperson for Watson insisted the NEC changes – which play into the hands of the anti-Corbyn movement – have been a long time coming and suggested the role of the deputy leader behind the scenes was overplayed.
"Scottish and Welsh Labour have been asking for five years that they should have a say on what happens on Labour's NEC," the spokesperson said. "Regardless of the political climate that is something that they should have had long ago."
But among both the pro- and anti-Corbyn factions of the party, it's Watson's name that crops up when asked who gets the credit for the NEC's actions, which have left the Labour leader struggling for a majority on the party's top table.
Jim Waterson is a politics editor for BuzzFeed News and is based in London.
Contact Jim Waterson at firstname.lastname@example.org.
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