Things must be atrocious when, as a Labour supporter, you end up yearning for the Michael Foot era. Yes, he was to the left of the public in an electorally untenable way. Yes, his presentation made him a sitting target to a hostile press. Yes, he led Labour to defeat. But he wasn’t Corbyn. He understood that the Labour Party exists to win power and put itself in the service of the country. He was principled – something that means a bit more than “committed to endlessly calling Tony Blair a war criminal”. He respected Parliament as an institution, too, and when he finally lost his MPs’ confidence after the 1983 election, he went.

He was a great speaker, writer and intellectual too. My favourite of his lectures is published in a 1983 pamphlet called Byron and the Bomb. In it, he makes the seemingly unlikely claim that poetry should be one of our first resources in opposing nuclear weapons: we must “grasp and imagine what a nuclear holocaust might mean . . . we must use our imagination in a way that has not been attempted before”, he writes.

If politics is to be more than glorified management, it demands people who can imagine better possible worlds and work out how to get us there. It demands people who can see absolute hell coming as well, and help us to avert it.

I didn’t see it coming last Friday. Of course, I knew it was possible that Remain could lose – the polls were extremely tight – and thought that Leave had run a vastly superior (and immensely dishonest) campaign. But on balance, I thought the result would be a narrow victory for staying in the EU. And one of the reasons I thought that was because the negative economic consequences of leaving had been so clearly laid out. When it came to the polling booth, why would a majority of Britons vote for that?

Well they did, because they didn’t actually believe it would be that bad. In the defence of Leave voters, nor did I. Because if I’d actually foreseen everything Brexit has caused over the last week, I would have been doing much more than cheerfully sharing articles on social media and looking forward to the least thrilling campaign in British political history being over so we could all go back to normal. I’d have been leafleting furiously. I’d have been prophesying at bus stops. I’d have been marching down the high street with a placard saying: “I have had visions of the Brexpocalypse and Project Fear isn’t the half of it.”

It was a total failure of political imagination on my part. Of course, I knew that a Leave vote would probably send the pound crashing; I knew that the constituent parts of the Union might want to fly in different directions if the individual countries had very different results; I knew that the Leave campaign had mercilessly exploited latent (and not so latent) British racism, and the consequences of that could be savage, whatever the result. But all those horrors came after the incomprehensible if of the result, contingencies hanging on contingency.

In my own defence, neither the architects of the Leave campaign nor the Prime Minister who called the referendum put any more serious thought into life after Leave than I did. But now the bomb has gone off, we have to apply our imaginations to it. We have to understand the full possible proportions of the disaster, if there’s any hope of avoiding the worst destruction.

The mixture is stunningly toxic. Our economy will shrink. There has already been a 50 per cent increase in hate crimes: in a breath, the word “leave” has been turned around against anyone perceived as an immigrant. The politicians claimed this was about getting Britain out of Europe, but a lot of people who voted for it would equally like to get anything they perceive as “non-British” out of Britain. And if the Union fractures, identity becomes even more fraught. A state that loses its boundaries rarely becomes more relaxed about the purity of its own population.

A populist-nationalist party like Ukip lives on the impossible ideal of excluding sinister “outside influences”, but it’s not alone in our politics. Centrist, inclusive Theresa May’s bid to lead the Tories included a promise to control migration; meanwhile, Labour’s (still) leader Jeremy Corbyn couldn’t launch a report into the antisemitism in the party without Jewish MP Ruth Smeeth receiving abuse from one of Corbyn’s supporters, who accused her of colluding with the media.

A tanking economy, an absent government, a collapsed opposition with a leader who is no longer even trying to work with Parliament but instead appealing directly to his mass support – and a public increasingly willing to put its resentments and anxieties into racial terms, and to put those terms into violent practice.

A week before the referendum, the compassionate internationalist MP Jo Cox was killed by a man who gave his name in court as “death to traitors, freedom for Britain”. A week after the referendum, accusations of treachery and frantic grabs for “freedom” are everywhere.

Just how bad could it be? Let’s be alarmist: really bad. Twentieth-century European history bad. Recessions, pogroms, the lot. It feels impossible, but then the last fortnight has felt impossible too. Lots of people would like to take lessons for Labour from Michael Foot, but the one that matters to all of us in our current political nightmare is this: we can only build better, safer futures if we’re brave enough to imagine – and ingenious enough to escape – the very, very worst.