Sir Keir Starmer
Sir Kier Starmer was raised by socialist parents who named him after Keir Hardie, the Labour leader's founder and a colossus of the socialist movement.
The current bookies' favourite to win the leadership, in Who's Who he refers to his parents Rodney and Josephine Starmer as 'Rod and Jo'.
The shadow Brexit secretary was an out-and-out Remainer who frequently clashed with Corbyn's inner circle over his overt support for a second referendum.
The 57-year-old lawyer, a former director of public prosecutions, was kept largely out of sight during the election campaign as the party tried, unsuccessfully, to hold on to Leave seats in the north.
Distrusted by hard left fans of Mr Corbyn, the Holborn and St Pancras MP set out his stall to be a unity candidate, attacking 'factionalism' and saying the party needed to include both Momentum and fans of Tony Blair.
And he dangled a carrot in front of Corbynites, saying he did not want the party to move too far rightwards.
He also played up his humble roots, with the Oxford-educated lawyer Sir Keir, who owns homes in London and Surrey worth more than £2million, saying in December: 'I know what it's like. I actually never had been in any workplace other than a factory until I left home for university. I'd never been in an office.'
He said he did not want a return to the era of Tony Blair, telling the BBC this morning: 'I don't need someone else's name tattooed on my head to make decisions.'
But he might face difficulty if he is seen as not left wing enough, or if the party feels it needs a northern voice to win back seats.
Emily Thornberry has been dogged by claims of snobbery towards working-class voters for years.
The shadow foreign secretary, whose Islington seat neighbours that of Jeremy Corbyn, was forced to resign from Ed Miliband's front bench in 2014 after tweeting an apparently mocking image of a house in Rochester with a white van and England flags outside.
Labour came third in the by-election in the constituency, which was won by Ukip.
After December's election failure she was embroiled in a furious row with ex-minister Caroline Flint, who lost her Don Vallley seat to the Tories.
Ms Flint claimed Mrs Thornberry told a northern MP privately that Brexit voters were 'stupid'.
Mrs Thornberry has angrily denied the allegation and threatened to sue Ms Flint.
A lively performer in Parliament, she has admirers among Labour's clutch of metropolitan MPs.
Ms Thornberry's London seat and vocal pro-Remain position could tell against her - although the membership is generally pro-EU.
Rebecca Long Bailey
The shadow business secretary is seen as the 'continuity' candidate, having been closely involved in Labour's lurch to the Left.
Frequently deployed on media, the 40-year-old's career has been pushed by shadow chancellor John McDonnell, who has long tipped her as a future leader.
Entering the contest she set out her stall saying she will keep pushing 'our socialist agenda', stressing her hard-Left credentials.
In a thinly-veiled swipe at rival Keir Starmer, she insisted she had not been happy with the party's Brexit stance in the election campaign, saying it had eroded 'trust in our communities'. She also admitted Labour should have been 'tougher' in addressing a wave of vile anti-Semitism among activists.
But Ms Long Bailey gave a staunch defence of Mr Corbyn, complaining that he had been