As candidates throw their hats into the ring, Paul Krishnamurty analyses the strengths and weaknesses seven trading below 49/150.0 in the betting...
"The case for Starmer will be made strongly by those calling for a return towards the centre ground, following the abject electoral failure of Corbynism."
Rebecca Long Bailey has key backing from the Left
POSITIVE: During Jeremy Corbyn's four years as Labour leader, the Left of the party assumed control of much of the internal machinery - the National Executive Committee, for instance - prompting a narrative that his allies are now in total control. If that is so, Rebecca Long Bailey will be hard to beat.
The Shadow Business Secretary has clearly been groomed for the job and promoted by John McDonnell - who has repeatedly called for a woman leader. It is widely reported that she will effectively run on a joint-ticket with friend, flat-mate and fellow rising star on the Left, Angela Rayner. Perhaps most importantly, she is in pole position to get the endorsement of the Unite union, led by Len McCluskey. This explains the earlier market move down to 10/111.9 although she's back out to 15/82.9.
NEGATIVE: Endorsements are a help but ultimately, this will be decided by several hundred thousand party members. Earlier polls among them show RLB trailing badly to the likes of Starmer and Thornberry. That suggests the members are not as left-wing as media legend would have it, and is in keeping with earlier signals that support for Corbyn had fallen back due to Brexit.
Heavyweight Starmer is the safe pick
POSITIVE: The case for Starmer will be made strongly by those calling for a return towards the centre ground, following the abject electoral failure of Corbynism. The knighted former Director of Public Prosecutions is a heavyweight - leadership material on conventional measures. He would be seen as a safe pair of hands, and expected to give Boris Johnson a hard time at PMQs. He led Yougov's last poll of Labour members.
NEGATIVE: Much depends on what conclusions members draw from defeat. If due to their backing a confirmatory Brexit referendum, that bodes ill for this arch-Remainer. Plus being a white male QC from London does nothing to appease grassroots desire for diversity, or to reach out to the lost heartlands in the Midlands and North.
Nandy's pitch to reunite the party could resonate
POSITIVE: Nandy ticks all the latter boxes. She founded the Centre for Towns think-tank, which warned starkly of Labour's disaster in the seats that always determine UK elections. Her acceptance speech on election night in Wigan - pledging to listen and learn from those lost Northern voters in order to rebuild Labour's lost coalition between 'Lewisham and Leigh' - was a powerful statement of leadership intent. She is on the 'soft Left' of the party and commands respect in the House of Commons. Definitely leadership material.
NEGATIVE: Her pitch could fall on deaf ears if this overwhelmingly pro-Remain audience refuse to change tack. Nandy voted for the Withdrawal Agreement at first reading. She also made enemies on the Left when backing failed leadership challenger Owen Smith in 2016.
Relatable Phillips could have wider electoral appeal
POSITIVE: Smacks of being very electable with the wider public. Phillips has developed a minor celebrity profile with TV appearances and memorable tirades against Boris Johnson in parliament. She comes across as ordinary and relatable. Expect plenty of MPs to support her.
NEGATIVE: Very unpopular with the Left of the party, ever since saying she would 'stab Jeremy in the front'. Her consistent defence of Tony Blair may still be out of step with the grassroots.
Lewis has an attractive pitch for the grassroots
POSITIVE: This former soldier and journalist would be the first black leader of a UK party and is sure to be a prominent Labour figure in the decades ahead. Lewis has a following within Momentum but has a more nuanced pitch than others on the Left. He advocates a 'progressive alliance' with other parties and supports electoral reform. That is very popular with the members, whom Lewis pledges to give a greater say in policy.
NEGATIVE: So far at least, he isn't as high-profile as those above him in the betting. Plus as an arch-Remainer and early backer of a second referendum, Lewis wouldn't offer anything to those Brexit voters who have abandoned Labour.
Cooper has credentials but missed her chance
POSITIVE: A parliamentary heavyweight who played a key role in the Brexit standoff. A senior minister under Blair and Gordon Brown, Cooper has long been regarded as leadership material but lost badly to Corbyn in 2015. If she runs, plenty of MPs would back her.
NEGATIVE: There's a strong sense she missed her chance when standing aside for her husband, Ed Balls, in 2010, and there's no obvious reason to think the members will want her anymore than in 2015. She nearly lost an enormous majority in her heavily-Leave constituency, presumably as she was very closely associated with 'Remoaners'.
Thornberry hampered by Islington Remainer brand
POSITIVE: One of Labour's principle reps in recent years, deputising effectively for Corbyn at PMQs and taking on the tough TV gigs. Members will respect her competence and loyalty.
NEGATIVE: Too Remain, too Islington. She denies saying her constituents were less stupid than those of Caroline Flint in strongly-Leave Don Valley, but the damage is done. Not least because it mirrors a previous controversy when she resigned from Ed Miliband's Shadow Cabinet after an apparently patronising tweet about the voters of Rochester.