More decisions were made (allowing families to mix on Christmas Day, for instance) and not made (there was no mass testing before schools reopened) that contributed to what followed. But the direction of travel had been set in a few days in mid-to-late September, and it brought on a second wave far worse than the first that cost tens of thousands of lives.

But for the vaccine rollout, Britain would now be back where it was then. This is a big but, of course. The rollout has been as successful as anywhere in the world – but because of this it carries two big risks: that those responsible for the second wave are never held to account for it; and that lessons which should be learned from it are not.

We hope that the vaccines keep the variant from India at bay. We hope the vast petri dishes currently incubating viral mutations in South Asia, Latin America and Africa do not produce more variants able to dance around the vaccine and make younger and younger people sick.

In the meantime, Johnson is subject to pressures that are all too familiar from last autumn. The Treasury and the a-scientific right wing of his party want him to stick with the plan to complete the reopening of the economy next month at almost any cost. In the opposite corner, government scientists, public health officials and health secretary Matt Hancock, annealed by 14 months of battle with Covid, favour an abundance of caution.

When forced to choose, Johnson needs to channel Hancock more, and Sunak less.

The judgments he has to make over the next three weeks are not easy. Jeremy Farrar of the Wellcome Trust has said they are in fact the most difficult of the pandemic so far. Johnson should be able to distinguish by now between sound science and bogus science, and he should know that public health does more to support the economy – never mind people’s lives – than a quick reopening of the pubs. But we are in uncharted territory nevertheless, thanks to the vaccines. They have made us safer but we don’t know how much safer. The vaccines are what makes these decisions difficult. Those of last September were easy by comparison, and Johnson still managed to call them wrong.

His guests on 19 September were professors Sunetra Gupta and Carl Heneghan, both from Oxford, and Anders Tegnell, the Swedish state epidemiologist responsible for his country’s controversial and ultimately doomed strategy of not locking down against the virus. 

They advanced the view that the social and economic cost of national lockdowns outweighed their advantages and that it should be possible to shield the vulnerable while letting those not seriously threatened by Covid get on with their lives – and get the virus if it crossed their paths. They were advocates of herd immunity, even though the first wave had shown that, without vaccines, this would only have been achievable with hundreds of thousands of deaths. As Professor Alan McNally of the University of Birmingham wrote later, their advice flew in the face of the opinion of the government’s most respected scientific advisers.

So why were they being zoomed into the cabinet room at Number 10? The short answer is that Sunak, riding high on “Eat Out to Help Out” and desperately anxious not to deepen the worst slump in 90 years, persuaded Johnson to give them a hearing.

The longer answer: Johnson, too, wanted an alternative to the tough lockdown advice he was getting from professors Chris Whitty and Patrick Vallance, most recently on 16 September, by which time it was clear that Covid case numbers had been rising fast since the reopening of schools two weeks earlier. 

Johnson wanted to be able to say he was still following the science, but he did not like what his most senior scientists were telling him. And so, as one senior NHS doctor who cannot afford to speak publicly puts it, he cherry-picked the science instead of following it. “Heneghan and Gupta have been demonstrably wrong all the way through and suddenly they’re called into the inner sanctum to give their blessing to a course of action that’s already been decided.”

The next day, Whitty and Vallance held their own press conference, warning that the way things were going there would be 50,000 new infections a day by mid-October and 200 deaths a day by mid-November. The day after that, Johnson ignored their advice to announce a circuit-breaker, ordering only mild restrictions on movement and commerce, even though the mass testing his government had promised was still nowhere in sight.

It was a moment when Johnson’s the-heck-with-it optimism and his ill-disguised incompetence peaked at the same time. Dominic Cummings, his senior aide, knew it, and there have been worrying echoes of it in the past week as hard data and magical thinking wrestle again for control of Johnson’s mind.

There are two grounds for hope: that the UK’s enormous vaccine stockpile and high vaccine uptake prevent a third wave; and that – third time lucky – Johnson sees the folly of depending on hope. This is his chance to act on the lessons of last September.

To recap, those lessons are:

• Following the science means following the scientific consensus, not assembling a spurious range of views in order to pick whichever plays best with the base.
• Dithering is always more expensive in the end – in GDP foregone as well as lives.
• And leadership in a pandemic means serving the public, not that small subset of the public represented by Treasury hawks, conservative newspaper editors and MPs from shire constituencies with high vaccination rates and low exposure to the real ravages of Covid. 

As someone once said, those who fail to learn from history – even very recent history – are doomed to repeat it.