A handful of recent polls suggest Labour is doing better than many expected at the start of the campaign. Whatever the reason, though, the gap between it and the Conservatives is still a yawning one. Bluntly, it remains the case that this election is not about whether Labour is going to lose, it’s about how badly.

What matters for Labour, then, is what happens next and that depends in part on how many parliamentary seats the party ends up with on 9 June.

Clearly, judging from its tax, spend, and nationalise manifesto, and from the study made of Jeremy Corbyn’s campaign itinerary by the BBC’s Chris Cook, the leadership is hoping not so much to win over undecided voters as to mobilise its base sufficient to match or even surpass Ed Miliband’s 30.4 per cent of the vote in 2015.

But while that might allow Corbyn and co to mount a rhetorical argument in favour of keeping him in place, it’s unlikely to be enough (owing to the number of Labour-held marginals that will inevitably fall to a resurgent Conservative party) to stop Labour dropping below two hundred seats. And if their plan doesn’t work, and Labour’s vote share ends up somewhere in the mid-to-late 20s, then the party could emerge from the election holding just a quarter of the available seats in the Commons.

Whatever happens, Corbyn will have to decide whether, like some of his predecessors, to stay on or, as Ed Miliband did in 2015, to accept responsibility for the defeat and resign immediately. If he stays on, it will presumably be not so much because he plans to be in the job for another full parliamentary term but because he hopes his being there will improve the chances of his being replaced sooner or later by another MP from the radical wing of the party – something made more likely, though by no means certain, should the parliamentary Labour party’s left manage to change the rules to reduce the number of nominations required to make it onto the ballot paper sent out to its largely left-liberal membership.

There are, however, two problems with this strategy. First, the left is not as good at grassroots organising as many assume, and there is no guarantee that they will achieve that rule change at Labour’s autumn conference. Second, Corbyn could well face a challenge before then anyway. And if he is challenged over the summer (names bandied around include Yvette Cooper, Chukka Umunna and possibly Dan Jarvis), then no-one should take it as given that he will win – not after a damaging election defeat and a possible change of heart on the part of those trade union leaders whose ideology does not trump their concerns about throwing their members’ good money after bad.

If, on the other hand, Corbyn resigns immediately after the party’s defeat, it will be because left-wing Labour MPs reckon they can count on 15 per cent of their colleagues in the PLP and the party’s delegation to the European Parliament to nominate one of their number for the leadership. Calculations vary, but this is by no means impossible, not least because Corbynite MPs are slightly more likely to escape losing their seats than the non-Corbynite MPs who will continue to make up the bulk of the PLP after the general election. Should they achieve their aim, Labour’s fate will again be the hands of its membership.

Again, though, we should be careful not to assume the party’s grassroots will automatically opt for another left-winger – a Corbyn clone or mini-me. Members value their principles, and many will doubtless buy into the argument that their hero Jeremy was traduced by the media and stabbed in the back by his "Blairite" parliamentary colleagues. But research suggests that party members also care about power as well as protest, so they won’t necessarily relish the prospect of a further five (and probably ten) years out of office.

That said, if Labour members do vote for Corbyn or another out-and-out seventies-style socialist (as opposed to a Neil Kinnock-style "soft left", compromise candidate), then we need to contemplate the possibility (if not yet the probability) that the party could suffer a potentially fatal split as the moderate majority of the PLP looks for a way out of what by then will look to many of them like a burning building.

Inertia, of course, is a much-underestimated force, and behavioural psychology teaches us that loss-aversion is just as powerful. On the other hand, so, too, is the feeling that sometimes you have nothing left to lose. If that applies to a substantial number of Labour MPs, then look past the election for a moment because this summer, like last summer, could be a truly historic one for British politics.