“Standing here saying this makes me want to cry,” said First Minister Nicola Sturgeon at a press conference on Saturday evening as she announced tougher restrictions. But those south of Hadrian’s Wall will be crying more, as London and much of the south east of England have been condemned to virtually full lockdown restrictions.

These “Tier 4” rules will shutter all non-essential businesses, including gyms and salons which remained open in Tier 3, and reduce the outdoor household mixing limit to just two people. This will come into effect at 00:01 tomorrow morning.

Most depressing is the fact that Christmas is now effectively cancelled for a third of England. Few people were planning large meet-ups in the first place, but this development will ensure, for many, a very lonely Christmas week. For young professionals living alone, Christmas 2020 will be an extended period of doom-scrolling through social media feeds. They won’t be able to travel to see family.

Speaking at a hastily-arranged Downing Street press conference, the Prime Minister said: “It is my duty to take the difficult decisions, to do what is right to protect the people of this country.”

Britain – and potentially much of the world – will through the coming months face the consequences of a change in the character of the coronavirus epidemic. The virus has evolved. While this is to be expected with infectious diseases, and while, thankfully, the evolved Covid is not more deadly, it is much more transmissible. The government believes it could be 70 per cent more transmissible – this is surprising, serious and incredibly consequential.

This new strain – named VUI2020/12/01 – has very rapidly got hold of Kent and London since the beginning of this month, providing an early indication of how it will change the game across the country in the coming weeks. The mutated Covid already accounts for 62 per cent of new cases in London, with some of the capital’s largest NHS Trusts suddenly overwhelmed by a wave of new hospital admissions.

Take a look at the admission figures to Barts NHS Trust in London. They’re rising at a frightening rate, and the trust is thought to be within days of being overwhelmed.

Now, a massive question mark hovers over whether Tier 4 restrictions will be enough to suppress VUI2020/12/01. Tier 3 restrictions failed immeasurably, and the national “circuit-breaker” last month failed to reduce the reproduction rate much. With this mutation predicted to be increasing the reproduction rate by around 0.4 per cent, some believe there is little chance that anything other than a strict national lockdown of the style we saw in March will make the epidemic shrink.

In any case, we should probably write off the first quarter of 2021. The vast majority of us will likely be under severe restrictions until the completion of phase one of the vaccination rollout.

At least there is some Christmas cheer in the fact that the approval process for the Oxford/AstraZeneca vaccine is now reportedly in the final stage, with a decision expected in the coming week. This will ease the logistical burden on the NHS and speed up the rollout by orders of magnitude. More help is on the way.