Liz Truss’s statement that she would never authorise another lockdown and The Spectator’s interview with Rishi Sunak have triggered a new debate about whether the lockdowns of 2020 and 2021 were justified. The most widely discussed positions are that lockdown occurred too late or that there should never have been any lockdowns at all, alongside the view that what happened was about right. But there is another position here – in many ways perhaps the most obvious position – that rarely gets an airing.

When lockdown was first introduced, Boris Johnson said the point was to ‘squash the sombrero’ of cases, so that the peak number of hospitalisations each week did not overwhelm the NHS. That was the original rationale for lockdowns, and it was an excellent one. At the time, we were being told that around 20 per cent of cases were leading to hospitalisation and the UK authorities estimated that in an unmitigated epidemic, 95 per cent of the expected 40 million infections would occur in a nine week period. So that was going to mean 7.6 million people in hospital in nine weeks versus 170,000 NHS beds, implying millions of people would have to go through severe Covid at home with only their loved ones to assist them. In the end, it turned out that rather than 20 per cent of cases leading to hospitalisation the actual number was more like 3 to 4 per cent, and that instead of 40 million infections it was more like 65 million, but the fundamental story would have been the same – millions of very sick people dealt with without formal medical assistance.

Some very significant restrictions – lockdown or something akin to it – were going to be required. But note that ‘squashing the sombrero’ was not supposed to mean stopping the spread altogether or eliminating the virus domestically. Some of you may remember a short video that went viral at the time, with a man pouring water into a bottle with a hole, illustrating that only with a steady flow of cases and occasional lockdowns to prevent overflow could the health system cope. Too early a lockdown would be just as likely to lead to health system collapse (after lockdown inevitably ended) as too late a lockdown would.

In that video it was assumed that only one lockdown was feasible. In its well-known March 2020 paper, Imperial College modelled an alternative scenario with a series of lockdowns and relaxations over a period of at least 18 months, with us being in lockdown around two thirds of the time and out of lockdown for about one third.

The first lockdown did not actually seek to ‘squash the sombrero’. If that had indeed been the point of it then we would have been released from lockdown after around three to four weeks, allowing a further phase of spread followed (if required) by another short lockdown to squash the sombrero again, and so on until the pandemic was sufficiently complete that we could leave it to progress without the health system being overwhelmed. Instead we had a long lockdown, lasting into late June, with cases numbers dropping to very low levels.

A long lockdown never had the remotest chance of eliminating Covid in the UK. Experts on elimination were unanimous on that. Only in isolated island countries such as Taiwan or New Zealand was that plausible (and even they were not consistently successful in practice). All a long lockdown would achieve was to take case numbers low so that when the second wave came – as it inevitably would – its peak would be higher. It was precisely for that reason that the Sage committee in early March did not advise a long tight lockdown.

That was precisely what happened. A second wave came. We had a second, shorter, lockdown, but that achieved very little except to buy time. As luck would have it, vaccines arrived just at that moment, changing the game altogether. But imagine that vaccines had not arrived as the second wave hit, and that it had still been thought vaccines might be 18 months to five years away and might be of limited value even when they did arrive. It seems very clear that the long lockdown policy would have been deemed an epic error and instead we would have been forced to attempt something else – probably a variant of the original squashing-the-sombrero policy, with a series of strategically-timed short lockdowns to prevent the health system being overwhelmed at the virus’s peak.

The only reason we do not deem the long lockdown of 2020 an epic error is the serendipity of the vaccines’ arrival. No one had budgeted for that when the initial lockdown was initiated nor when it was maintained as long as it was. The inquiries now should be into why the government ignored the clear scientific advice – which would have been deemed vindicated by events – that a long, tight lockdown would be counterproductive in leading to a larger second wave that would hit in winter instead of summer, meaning a vicious combination of the country’s liberties being smashed through authoritarian house arrest of the entire population combined with more actual deaths as the epidemic peak was higher and more poorly-timed (seasonally) than it would have been had the scientific advice been followed.

Perhaps in a future pandemic we should believe that vaccines or therapies will come quickly and so an early and long lockdown to buy time will be the correct strategy. But if vaccines do not come, the inescapable logic of a highly transmissible, highly-hospitalising virus will be the same as it was in early March 2020. Short lockdowns may be necessary and useful to prevent health system swamping. But long lockdowns make things worse, not better.