I think of the young canvassers – thousands of them – who were out on the doorsteps for the first time, in cold and miserable weather, lit up by a politics that spoke to them and for them as no political party had done before. They will be told they were wrong to believe in it. They were not.

I think of the woman, a carer for her disabled brother, who said that her life had got worse for years and years, and politicians always promised it would get better, and it didn’t, and how could she trust Labour? I think of the man who voted Labour in 2017, but wouldn’t now, because his Polish partner was scared of living here much longer. And the man who said you can’t change anything anyway, because ‘it’s all fucking rigged even when you win, look at Brexit.’

There wasn’t an obvious way for Labour to have won this election. The usual bromides will be offered up: it was Corbyn, no, it was Brexit, no, it was the manifesto, no, it was the press, no, it was credibility. All of them are in various ways true, but in all ways only partial: attitudes to Corbyn have hardened considerably since 2017; Brexit blew open a long persistent crack in Labour’s voter base; the press is execrable and even harder to deal with in the digital era. The manifesto was a bold attempt to grapple with the problems of the 21st century, and many of its policies are extraordinarily popular, but it was a document presented as if to allies, rather than to a sceptical electorate uneasy with its trust. There are other consolatory rationalisations, also insufficient: 2019 saw a return to the secular decline in Labour’s vote share, and 2017 looks like an outlier; the first-past-the-post electoral system, which had helped in the past to conceal disenchantment with the party, turned its brutal edge against it.

Anyone who claims that Labour’s leftward shift was the product of a cultish devotion to one man, and will disappear on his departure, doesn’t understand its origins or its implications. The party now has a campaigning left-wing membership that’s serious about climate change, public ownership and defending migration; no successor to Corbyn will be able to abstain on welfare bills, or promise to cut ‘harder and deeper than Thatcher’. Many who have always opposed such politics will declare it toxic, and inimical to victory ‘from the centre’. But the electoral wasteland confronting the avowed centrist parties in this election suggests that wasn’t where Labour’s lost vote went.

There are many lessons for the Labour left to learn from this election: five weeks’ enthusiasm cannot make up for decades of neglect; campaigning is about listening as much as listing policies; the conventional political virtues – presentation, messaging, and ruthless attacks on one’s opponents – can’t be circumvented by a surfeit of positivity. But without intransigent principle they are barren. All of these questions – how to blend movement and machine – will bear down on whoever is elected as Corbyn’s successor, but they are also questions the party must ask itself.

And it must find its answers quickly. Boris Johnson is in a position of strength, and desperately requires opposition, not only in parliament. His timetable on Brexit will falter in June, when he is confronted with the question of whether or not to extend the transition period. He will doubtless want a range of gaudily authoritarian social policies to distract from it. He is set, too, for confrontations over Scottish independence, especially when Brexit intensifies in the early part of next year. The defeat will have left Labour dizzy, grieving and distraught, in need of self-examination and honest dialogue. But it must prepare to get back up and fight.