“The polls suggest that Starmer is on course for a landslide. They may be wrong. Or they may turn. But if they don’t, the Conservatives may find themselves asking voters whether they really want to hand Labour a three-figure majority — and say: ‘Don’t give Starmer a blank cheque.’”

Political commentators glide noiselessly over their prediction failures. (I could list many.) And trumpet their triumphs, or whatever passes for them. So I take you back to the quote above, which I gave to the Observer on May 24.

The polls may be wrong. But they haven’t turned. And the Tories are indeed going where I thought they would go.

It started on the doorsteps, unauthorised by Number Ten. By at least the middle of last week, Conservative candidates could feel the chill in the polls and the electoral wind settling in. “Look, I know Labour’s going to win,” some began to tell undecided voters. “But you don’t want anyone to have a landslide, do you? And you know that I’m a decent local MP. So vote for me to keep Starmer in check”.

But you only have my word for it (unless you’ve picked up the same information yourself). So here’s some evidence.

Last weekend, Conservative social media adverts claimed that voting Liberal Democrat or Reform could swell the size of a Labour majority — and so hand Keir Starmer, yes, “a blank cheque”. On Tuesday, Grant Shapps warned that a Labour landslide — a “supermajority” — would grant Sir Keir Starmer “unchecked power”. Yesterday, Rishi Sunak said that Labour is asking voters for “a blank cheque, without telling them what they are going to do with it.”

More of the same will come.

Now, there is a Tory case both against and for this argument. The former runs roughly as follows.

It’s hard to persuade people to vote for a Government. But it’s harder still to get them to vote for an Opposition: it’s not how the electorate usually calibrates its choice and it’s difficult to get it to change. Furthermore, people like to back a winner.

And there are knock-on consequences that must be thought through. Admit defeat, and retreat becomes a rout. Disciple breaks down altogether. The blame game becomes the only one in town. Ministers, aides and MPs brief against each other. Leadership candidates break cover. The campaign gives up even pretending not to collapse. The cure is worse than the disease.

The counter-case is that people don’t necessarily like to back a winner: Jeremy Corbyn’s lift-off during the 2017 general election campaign began as a protest against a potential Conservative landslide. The polls tell us, first, that voters want Labour to win and, second, that neither the party itself nor its leader are popular — because no leader or party is.

Put those two together, and common sense suggests a Labour majority of, say, 75 — not the 1931 general election-type landslide that the polls say would happen were the election to take place today. Which would leave Labour as overweening now as the National Government was then, with Sir Keir as a modern Stanley Baldwin. If people are resistant to the prospect, shouldn’t Sunak and company draw it to their attention?

Now you can argue the toss one way or the other. But the brutal truth is surely that, as matters stand, the Conservative have no other option left. They have run out of road — or so it seems.

D-Day, Downing Street rain and £100 bets aside, the Tories have run a neatly crafted campaign, complete with attention-catching policy announcements, a gaffe-free manifesto and well-honed attacks on Labour’s tax plans. Sunak even won the only head-to-head television debate with Sir Keir to date. And none of it appears to have moved the polls. No, I take that back. They have moved: they’ve got worse.

The proximate cause, of course, is Nigel Farage’s candidacy in Clacton, which delivered Reform the required publicity voltage. The significance of this week’s YouGov poll showing it pushing the Conservatives into third place may be more psychological than psephological, but it sets the campaign up nicely for its second half.

Course One is that the hype which created Reform now destroys it, as what Tony Blair called “the feral beast” — the media — turns on Farage and his party. Reform’s candidates are exposed. Its manifesto shredded. Its ratings begin to drift down as the Conservatives put the squeeze on.

Labour’s do the same (as they already have in some polls), as the Greens and Galloway eat away at it. The Liberal Democrats run out of slapstick to inflict on their leader. TV debates dry up. The Tories end up with 200 seats, even perhaps more. Given recent history, that would look like a triumph.

Course Two is as above: degringolade; downfall — even, in the very worst of all Tory worlds, real crossover, with Reform grabbing a higher percentage of the vote. As I write, neurotic Conservatives are tapping percentages into Electoral Calculus, that crude but convenient tool, to work out what the consequences could be.

One of the features of first past the post is that Reform has to haul its vote well clear of the Tories to gain more seats than them. The prospect is vanishingly implausible. Not to mention irrelevant — to the government of Britain for the next five years, at least, and plausibly for the next decade and more.

The bill will arrive in due course

For if the polls carry on as they are and are right on the day, Sir Keir will be less a second Attlee than a second Baldwin, peering contemptuously down at midget rivals: Tories, LibDems, Farage and company (maybe), a smattering of Greens, a diminished SNP. Baldwin won another thumping victory in 1935. It’s hard to believe that his majority of 254 in that year would have been overturned in a 1940 peacetime election. The precedent should be sobering.

But for the moment, it’s time for revenge on the Conservatives. So live for today — and don’t start thinking about tomorrow, as Fleetwood Mac didn’t quite put it. Stuff the Tories and damn the consequences. Party like it’s 1997, but even better.

The bill will arrive in due course. And the hangover will last a very, very long time.