We don’t yet know whether it will be Angela Eagle or Owen Smith, or maybe both of them, who ends up running against Jeremy Corbyn for the Labour leadership. But what we do know – because we reckon we now know lot about the people who will vote in that ballot – is that any challenger is going to have their work cut out.

We surveyed Labour members just after the 2015 General Election, and then ran a second survey in May this year so we could capture those who joined the party after the election.

Now, for the first time, we’ve put those two surveys together in order to come up with a pen-portrait of those people who, because they were members before the NEC’s February cut-off date, will therefore be eligible to vote over the summer. You can find the more detailed figures here.

Labour’s grassroots members will almost certainly make up the bulk of those who choose the party’s leader over the summer. So what do they look like? And how do they think?

By our reckoning, Labour’s leadership contest is going to be decided, for the most part, by less than 400,000 mainly middle-class university graduates. Nearly half of these members – unlike many of Labour’s voters – live in London and the South of England. Some 75 per cent of Labour members are ABC1 voters, and 57 per cent of them have a degree. Around 15 per cent live in London and 32 per cent live in other parts of the South of England. Only 28 per cent live in the party’s northern heartlands and 20 per cent in Wales and the Midlands, where (think, Nuneaton) any party wanting to win a general election desperately needs to win over voters.

Because a relatively large proportion of those who joined the party after the general election were women, the Labour membership has become a little more gender balanced, with a 55:45 male/female split. The average age, however, hasn’t changed much: it’s still 51.

That might have something to do with the fact that roughly a third of the post-election joiners had been Labour members previously. Many of them appear to have returned after leaving in the New Labour era. They may possibly have replaced some of those who left the party because they didn’t like the direction it was taking under Corbyn.

Those voting in Labour’s leadership contest are socially very, very liberal. Only 22 per cent believe law-breakers should be given stiffer sentences and only 10 per cent support the death penalty. Some 84 per cent back gay marriage. They are also very positive about immigration. On a seven-point scale running from immigration being bad for the economy (1) to it being good for the economy (7), they score it at 5.74. On a similar scale which asks about the cultural benefits of immigration they come up, spookily enough, with exactly the same score.

On economic issues, it’s as if Blair and Brown (or at least the "neoliberal" Blair and Brown of the left’s imagination) never existed. Labour’s grassroots members are almost unanimous in favouring redistribution (92 per cent), in distrusting big business (94 per cent) and in believing that government public spending cuts have gone too far (95 per cent).

Asked to place themselves on a left to right scale running from one to ten, the average Labour member locates him or herself at 2.17. Nearly one in ten members voted Green in 2015 – something that was notably more common among those who joined the party after that general election. Irrespective of when they joined, however, eight out of ten wanted the UK to remain in the European Union.

When asked what they’re looking for in a leader, Labour’s members are not unduly concerned with a leader’s ability to radiate strength and authority, or his or her capacity to unite the nation. Only around a third of them put a premium on having a leader who can appeal to the average voter. Interestingly, though, this did matter more to those who were already members by the time of the 2015 general election than those who joined after it.

Ultimately, what matters more to Labour members, it seems, is having a leader who, as well as being a good communicator, is in touch with ordinary people and has strong political beliefs – something that is especially true for those who joined after rather than before the last general election.

Whether Jeremy Corbyn or either of his challengers can tick all of these boxes is, we suspect, in the eye of the beholder. Still, given who Labour members are and how they think, we suspect Mr Corbyn is going to be awfully hard to beat.