Statistically, a Tory victory at the next election is unlikely. British voters tend not to grant a fourth term to governments: it has happened only once in our post-war history. That was under John Major in 1992 in an election in which the government lost 40 seats. But this time, the Tories would go into a general election as a minority government. If this were not handicap enough, they’ll also have to fight the election having spent years dealing with Europe, the subject that splits the party most deeply. Yet, remarkably, the Tories are still in with a chance of winning a fourth term. They have one man to thank for this: Jeremy Corbyn.

If Labour were led by a more conventional figure, politics would be very different. Another opposition leader would be able to tempt more Tories to rebel in pursuit of a soft Brexit. But Corbyn’s left-wing economics, dubious associations and personal Euroscepticism mean that even the most Europhile Tories aren’t inclined to align themselves with him. Corbyn also has problems with the electorate more broadly. A poll this week showed that two-thirds of people think the government is handling Brexit badly — yet still the Tories have a five-point lead. This suggests that doubts about Corbyn, rather than enthusiasm for the Tories, explain the current state of the polls. Further evidence for this is provided by another poll which shows that 72 per cent of voters disapprove of the job Corbyn is doing as leader of the opposition.

Corbyn has a unifying effect on the Tories. There is a sense that whatever their divisions, they mustn’t let someone with his views become prime minister. Without such a bogeyman, the Tories would be even more split than they already are.

Cabinet ministers, though, are wary of Tory complacency over Corbyn. They point out that almost no one predicted he would get 40 per cent of the vote at the last election and cost the Tories their majority. They also argue that he has held his electoral coalition together over Brexit with some political skill. But this, perhaps, is Corbyn’s problem. His whole appeal was based on the idea that he wasn’t just another calculating politician but a man of principle. So where is that principle with regard to Brexit? He has looked as tactical and cynical as any politician on this subject. His approach has been anything but the ‘straight-talking honest politics’ he promised.

Corbyn is a Bennite Eurosceptic leading a party with a fervently pro-Remain membership that needs to hold and win a slew of Leave-voting constituencies to form a government. To date, Corbyn’s approach to this problem has been to try to allow Brexit to happen without Labour’s fingerprints on it. But the parliamentary arithmetic is making this increasingly difficult to pull off. What Labour does will be crucial to what happens.

Labour members want a second referendum, but Corbyn has all but abandoned this as an option. This will cost him support. They won’t be singing ‘Oh, Jeremy Corbyn’ at Glastonbury this year.

If Brexit does go through, a split in the Labour party is highly likely as Nick Cohen writes in this week’s issue. Many of Corbyn’s strongest internal critics have stayed in the party in the hope that they could use Labour to stop, or significantly soften, Brexit. If they fail in that attempt, they’ll have little reason left to stay. Another factor is that many Labour MPs felt they could safely remain in the party at the last election because Labour was so far behind in the polls that there was little chance of Corbyn becoming prime minister. But he’ll start the next campaign within striking distance of No. 10.

All of this risks encouraging complacency on the Tories’ part. It is tempting for them to think that if they can somehow get a Brexit deal over the line, Labour will split and a fear of Corbyn will help stick the old Tory electoral coalition back together. Big business will come back to the Tories because it will be worried about higher taxes under Labour. That same fear will bring upper-income Remain-inclined voters back into the fold. Simultaneously, those traditional Tory voters disappointed that May’s Brexit isn’t hard enough won’t want to risk putting an old-fashioned left-winger into No. 10 and will swallow their anger and vote for the party.

But this is dangerous thinking. The Tories haven’t done enough to address the reasons that Corbyn did so well in 2017, increasing Labour’s share of the vote by more than any leader since Clement Attlee. One of the main reasons why such a left-wing Labour party could get 40 per cent of the vote was that so many under-40s think they are never going to become home-owners: you can’t expect people without capital — or a realistic chance of obtaining it — to be capitalists.

Indeed, the swing from the Tories to Labour was principally driven by renters. May responded by saying that she wanted to ‘dedicate’ her premiership to ‘fixing our broken housing market’. But as with her other ‘burning injustices’, her policies have not matched her rhetoric. Until home--ownerships levels return to what they were in the early years of this century, Corbynism will continue to have considerable electoral appeal.

The housing market is only one example of where the Tories need to find answers. Another is sluggish wage growth. In real terms, UK wages are still below pre-2008 levels. Solving this requires a plan to make the UK more productive, which in turn requires upgrading the country’s physical and digital infrastructure.

Ultimately, though, the reason the Tories shouldn’t be complacent is that governments lose elections, rather than oppositions winning them. It is hard to imagine that the Tories could electorally survive either no Brexit or no deal, particularly given how late in the day preparations for the latter have been left. A snap election to break the Brexit logjam would sorely test voters’ patience.

Corbyn might have given the Tories a chance of winning a fourth term, but he has also raised the stakes for them. If they fail, this country will have a government that will fundamentally change the nature of the economy and our security relationships. It would take the Tories a generation to unwind them. The next few weeks and months will do far more than just determine how the UK leaves the European Union.