Jeremy Corbyn has won the right to personally contest a legal bid aimed at taking his name off the Labour leadership ballot.
Labour donor Michael Foster had launched a High Court challenge against the party's decision to automatically include Mr Corbyn in the upcoming leadership election.
That decision had been agreed by Labour's National Executive Committee after conflicting legal advice suggesting that Mr Corbyn should be both included and not included.
Other candidates in the election will have to seek nominations from MPs and MEPs in order to appear on the ballot paper. Mr Corbyn's limited support in the parliamentary party means this would likely be difficult.
Labour's NEC decided that as an already leader Mr Corbyn would not have to seek nominations in order to stand; the party's rulebook was ambiguous on the subject.
The legal challenge against the decision by Mr Foster had named Labour's general secreatry Iain McNicol as the defendent in the case.
However, Mr Corbyn launched a legal bid to get himself included as a second defendant. That bid has now been successful, with the High Court ruling on Wednesday morning.
His lawyers had argued that his own personal interest in defending the litigation was "pressing and obvious" and that he was not adequately represented in the same way as other Labour members by Mr McNichol.
The case of Mr Foster's challenge is now expected to be heard next week on Tuesday July 26, with Mr Corbyn attending court on that date.
The court decision comes a day after former shadow business secretary Angela Eagle dropped out of the Labour leadership race, leaving Owen Smith and Mr Corbyn as the only candidates.
MPs and activists critical of Mr Corbyn and who want him removed believe a unity candidate would be better able to tackle the leader.
A Times/YouGov poll of Labour members however shows the sitting leader with a significant lead.
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