And just like that, the world turned upside down.

Just a few short weeks ago Theresa May set out to grind her divided opposition into dust with a snap election whose express purpose was to deliver a crushing majority. Few would have bet against her doing so. Even three weeks ago, when her 20-point lead started to narrow, she still gave every impression of cruising towards a comfortable victory. Hours before the exit poll, gloomy Labour MPs were still predicting a bloodbath. Gossip about putative leadership candidates’ campaigns was starting to spread. Resignations were expected.

Well, forget all that. If tonight’s exit poll forecasting no overall Conservative majority is right – and the crucial cautionary note is that in 2015 its predecessor did underestimate the scale of David Cameron’s victory – then tonight is Jeremy Corbyn’s night, and May could yet become the shortest-lived British prime minister in half a century.

Imagine how they’ll be poring over this exit poll in Paris, Brussels and Berlin

At best she can expect to be returned as prime minister on a slender majority, facing the full wrath of a party that was confidently expecting nothing less than a demolition of Corbyn, and a free pass to do as it liked. At worst, she will have thrown away her predecessor’s hard-won majority for nothing – one imagines crockery is currently being thrown with some violence chez Cameron – and won’t even have the lifeline of a coalition with the Liberal Democrats to fall back on, since Tim Farron has made clear he isn’t going down that road again.

This was an election nobody really wanted, fought for reasons that are barely any clearer now it’s over, and it looks as if voters may well have called her bluff. But if so, we are sailing into uncharted waters now.

Whoever forms the next government will still arguably have a mandate for Brexit, thanks to the referendum. If the Lib Dems do experience only a modest recovery, winning the 14 seats predicted, that suggests there isn’t much appetite for a re-run. But what kind of Brexit we get must be completely up for grabs. This is no mandate for the hard, uncompromising version May sketched out; after all, Corbyn campaigned on a soft Brexit platform, stressing continued access to the single market, and Ukip is expected to lose its only seat. Plenty of wriggle room there for remainers in parliament. And imagine how they’ll be poring over this exit poll in Paris, Brussels and Berlin.

But the real story tonight is a human one, and it’s that of Jeremy Corbyn. Mocked, derided and discounted from the start, he has utterly transcended what were admittedly low expectations; and even if he doesn’t win the election, he must have secured a victory over the sceptics in his own party. It looks very much as if he has earned the right to stay on as leader, and this time with the full-throated backing of his MPs.

We were told Corbyn was ‘unelectable’. His fightback shows he’s anything but | Gary Younge Read more

For if the exit polls are right, the “surge” identified in the final weeks cannot simply have been confined to a few university towns. Vindication, perhaps, for the idea that the young and the politically marginalised can be engaged with big, bold ideas. And vindication almost certainly for the idea that millions of people across the west are more hungry for change – for something new, for things that conventional politicians aren’t saying, even if it’s not entirely clear how it all adds up – than political elites understand. So much for the long-established rule that political parties get nowhere unless they’re trusted on the economy (on which the Tories still lead Labour). So much for what we thought we knew about slick campaigning and soundbites – or indeed about the power of the rightwing media, which Corbynites were convinced would scupper them. Who’s afraid of the Sun and the Daily Mail now?

The night is still young, and much remains unexplained. There may well still be bad news to come in pockets of Yorkshire or the Midlands, where Labour MPs have been unrelentingly gloomy about their chances until now. It remains true that there is only so far a leader can get while continuing to ignore the mathematical reality of first-past-the-post, under which parties essentially win outright majorities only by persuading voters in marginal seats to change party.

But as things stand, this is undoubtedly Corbyn’s night. He has demonstrated that passion and energy matter, as much if not more than basic competence; that voters want to be inspired more than to be lectured. And once again he has proved the lesson that Donald Trump and Emmanuel Macron and Brexit should surely by now have taught us: that this is no longer the world we knew. Change is coming, if not already here.