Indeed, it’s this new variant that has led to the Government’s U-turn on Christmas plans, essentially cancelling festivities for millions of people now placed under new, Tier 4 restrictions just days before the big event.
Other countries are worried too. As this article is written, thousands of lorry drivers are stranded along motorways as they attempt to cross the Channel into France – they’re being denied entry due to the new variant.
Neighbouring countries are shutting down flights, and placing restrictions on British travellers – they don’t want this quickly spreading variant on their patch.
But have world leaders managed to contain the ‘new’ virus to just the UK, or has it reached mainland Europe and elsewhere yet?
Here is everything you need to know.
What is the new variant?
The new variant of coronavirus – known as VUI-202012/01 – has been linked with an exponential rise in coronavirus cases in the south-east of England, with experts saying the new variant is more transmissible than others.
Health Secretary Matt Hancock first told MPs on Monday 14 December that a new variant of Covid-19 had been identified, and that it was spreading in some areas of the country.
The new strain was first detected in September, and in November around a quarter of coronavirus cases in London were caused by the variant.
As it has spread quickly, scientists believe it could be 70 per cent more transmissible than other variants, though research is ongoing to try to understand exactly what the variant means for the UK.
Has it spread to other countries?
Genomic researchers have found the new and more infectious variant of Covid-19 has already spread around the UK, with cases identified in Wales and Scotland.
The Covid-19 Genomics UK (COG-UK) consortium sampled cases around the UK and found the variant is also in the South West, Midlands and North of England, areas that are under Tier 2 and 3 restrictions.
“It is certainly not isolated in one place, it has begun to spread to many places in England,” said Professor Tom Connor, a genomics expert from Cardiff University who has sequenced more viruses in the past week than the whole of France during the pandemic.
Where has the variant spread to?
World Health Organisation's COVID-19 technical lead Maria Van Kerkhove confirmed on Sunday (20 December) nine cases in Denmark, and a number of others in the Netherlands and Australia.
Italy's health ministry have also said a couple landing at Rome's Fiumicino airport tested positive for the new mutation and were in quarantine; Boris Johnson's spokesperson also revealed that the British overseas territory of Gibraltar had identified a case.
Professor Connor said it was no surprise that a new variant had been found in countries – including the Denmark and the Netherlands – which have mature sequencing systems set up, and he believed similar variants will pop up around the world.
New variants found in the UK, South Africa, Denmark and the Netherlands led to Germany banning travel from those countries.
France and South Africa believe they have cases of the mutation, but these have not been confirmed; French health minister Olivier Veran said it is "entirely possible" the new variant is already circulating in France, but no cases have been officially identified.
Why is the UK variant getting so much attention?
That doesn’t necessarily that the UK variant is the only new strain in circulation, and the reason the UK was one of the first countries to find a variant of note first is down to the vast amount of research being done on the virus here.
Sharon Peacock, director of COG-UK and a professor of public health and microbiology at the University of Cambridge, said: “We’ve sequenced 150,000 genomes which is about half the world’s data, so if you’re going to find something anywhere you’re going to find it probably here first.
“If this occurs in places that don’t have any sequencing you’re not going to find it at all.”
What that means, is that there could be – and almost certainly are – many more variants of coronavirus dotted all over the globe, they just haven’t been found yet.
However, since these variants are not suspected to be any more transmissible or deadly than Covid-19 already was, they will not have received the same attention at the UK’s variant.
How common are virus variants?
These mutations are extremely common in viruses, which happen as they are passed from person to person over a period of months.
The virus behind Covid-19 is a RNA virus, which means that genetically it is more prone to mutations, unlike DNA viruses like smallpox.
Mutations are a part of the natural process of an RNA virus and are very common, and since coronavirus started to spread across the world, it is thought that it has been mutating twice a month to find the most effective way to infect humans.
Sometimes, a virus mutates in a way that makes it worse at infecting people - and the new strain can then die out.