The race now moves onto supporting nominations from constituency Labour parties: who will emerge the strongest?
As Theresa May heads to Downing Street uncontested, the opposition parties want an early general election.
Eagle's launch has done nothing to dent the mood of optimism in Team Corbyn's ranks.
The leader will be automatically included in the party's contest without nominations, senior figures say.
The legal Catch 22 that requires a Commons vote, which could fox Brexit.
Senior party figures believe Labour's National Executive Committee could rule that the leader requires 50 MP/MEP nominations.
With Angela Eagle expected to challenge the Labour leader imminently, Len McClusky and other union representatives have declared their support for Corbyn.
Talks between the Labour leader and the unions, brokered by deputy leader Tom Watson, have been abandoned.
Jeremy Corbyn's chances of success aren't quite at 100 per cent - but they're close.
Each week The Staggers will pick a new word to describe our uncharted political and socioeconomic territory.
Equality of representation matters - even when it's difficult, says the director of the Labour Women's Network.
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