Passengers from South America, Portugal and Cape Verde can no longer enter the UK under a new travel ban.
The new rule, which came into effect on Friday 15 January, was put in place over fears of a new strain of Covid-19 detected in Brazil.
It comes as a leading scientist advising the UK Government said one of the two Brazil variants had already been found in Britain.
This is everything you need to know about the new South America travel ban, the countries that it affects, and when it could be lifted.
Which countries does the ban affect?
The UK-wide ban applies to passengers that have come from, or through, the following countries in the last 10 days:
Argentina, Brazil, Bolivia, Chile, Colombia, Ecuador, French Guiana, Guyana, Paraguay, Peru, Suriname, Uruguay and Venezuela.
But the travel ban also applies to Portugal, due to its strong ties to Brazil, and Cape Verde, the former Portugese colony.
Passengers coming from Panama in central America are also subject to the ban.
As Mexico, a popular holiday destination for Brits, is in North America, it is not included in the ban.
Is anyone exempt from the ban?
There are a couple of exemptions from the travel ban.
British and Irish citizens, and foreign nationals who have residence rights, are still allowed to return to the UK.
However, upon their arrival they must self isolate for the standard 10 days.
Hauliers coming from Portugal to transport essential goods are another exception to the rule.
Why has the ban been imposed?
The travel ban has been imposed due to concerns about the new strain of coronavirus first spotted in Brazil.
Like the UK’s new variant, and the one from South Africa, it is thought the Brazil variant could be more transmissible and there were fears that it could quickly spread through Brazil and the other countries it borders.
Ministers decided to instate the travel ban as a “precautionary” measure to prevent the new strain being carried into the country by passengers.
UK Transport Secretary Grant Shapps told BBC Radio 4’s Today on Friday 15 January that he did not believe that the new variant had arrived in the UK.
However, Prof Wendy Barclay, who leads the G2P-UK National Virology Consortium, a new project which studies new Covid mutations, contradicted Mr Shapps by saying one of the new strains from Brazil had in fact been found in the UK.
She said: "There are two different types of Brazilian variants and one of them has been detected and one of them has not.
“It was probably introduced some time ago.”
She added that the Brazil variant was being traced “very carefully”.
When will the ban end?
No definitive end date has been given for the travel ban, with Mr Shapps saying “he can’t provide an end date”.
Many central and South American countries had already imposed a travel ban from the UK due to the new strain identified here.
What is the Brazil variant?
Brazil's new strain of coronavirus was first identified in July.
It was recently discovered in four travellers who had arrived in Japan from the South American country.
It is similar to the other variant found in South Africa, as it has three key mutations within the spike protein.
The spike protein is the part of the coronavirus that latches onto human cells, so changes to the protein mean it may be better at infecting humans.
For this reason, experts are confident that the UK, Brazil and South Africa strains are more contagious and have the ability to spread quickly throughout the population.
However, although they could be more transmissible, there is no evidence to suggest that the new strains can cause a more serious illness.
Currently, scientists are still confident that the vaccines should work against them - although maybe not as well.
More research is being carried out on the new variants so scientists can understand them better.