Protection against hospitalisation can drop to as low as 60 per cent six months after the second dose, according to the UK Health Security Agency, which led to calls to speed up the program as the oldest part of the population surpassed this point.

Data shows that throughout October, the amount of virus circulating was increasing, with up to 50,000 cases a day, driven primarily by huge infection rates in school-age children, taking the total number of infected individuals to more than a million.

However, half-term and very high levels of immunity in schoolchildren stymied the unrelenting spread and infections in under-18s have now decidedly peaked and plummeted.

But Prof Woolhouse warns that while there is room for optimism, there is no space for complacency.

“I think if the booster campaign goes well and if we are also able to extend the vaccine to vulnerable people, then I’m optimistic,” he said.

Prof John Edmunds, an epidemiologist at the London School of Hygiene and Tropical Medicine and a leading advisor to the Government, sitting on Sage, Nervtag and SPI-M, says that with around a million people infected and an R rate around 0.9, there will likely be more than a million new cases before Christmas.

“I think we’d be in a pretty bad position if we didn’t booster, particularly before Christmas,” Prof Edmunds said.

“We are in a much better position than we were last Christmas. We have lateral flow tests which are very effective. This will help modify a lot of risks – if you have a lateral flow test and it’s positive, don’t go and see granny.”

Prof Neil Ferguson, the epidemiological modelling expert whose graphs thrust the nation into the first lockdown in March 2020, said on BBC Radio 4 on Saturday: “I think it is unlikely we will get anything close to what we had last year, that catastrophic winter wave.

“We might see slow increases as we did in October, for instance, but not anything as rapid as we saw last year.”

While the Covid landscape going into deepest winter shows glimmers of hope, the NHS is still operating at full tilt, with scarcely any beds unused.

Currently, 94.7 per cent of all hospital ward beds are occupied, the highest level since the pandemic began, but just one in 14 is a Covid patient compared with one in three at the peak.