As one leadership contest ends, another begins. Angela Eagle has submitted the 51 MP/MEP nominations required to stand and will now seek to replace Jeremy Corbyn. Labour's National Executive Committee will meet at 2pm tomorrow (Tuesday) to determine the terms of the contest, including whether Corbyn is automatically on the ballot. The party's HQ and the leader's office have received contradictory legal advice on whether he requires 51 nominations. But it is the NEC that will ultimately decide.

Those I spoke to yesterday suggested that the 33-member body could rule that Corbyn requires nominations - if a secret vote is held. But senior Labour figures told me this afternoon that there is "no doubt" that the leader has the numbers required to prevail ("whatever the legal advice"). As well as left-wing allies on the NEC, Corbyn crucially retains the backing of the 12 trade union delegates. A senior source told me the unions' support was "on lockdown" even in the event of a secret ballot (which would itself require an initial show of hands). "Unite are flying Martin Mayer in by plane. The TSSA delegate has cancelled her holiday," he said.

It is uncertain whether Corbyn will be permitted to attend the meeting. "Most of the time those with an interest leave," an NEC member told me. "It will be improper if he does." On the Andrew Marr Show yesterday, Corbyn warned that he would launch a legal challenge if he was not automatically on the ballot. A former shadow cabinet member suggested that the rebels could also seek to overturn the NEC's expected decision. "This is going to end up in court either way".

But following Eagle's launch and Theresa May's coronation, all the momentum is towards a swift contest. Owen Smith, who is considering standing, will now decide whether to fight Eagle to become the rebels' "unity candidate".