Published18 minutes ago
Travel from Brazil to the UK could be banned in response to the discovery of a new coronavirus variant.
Ministers are meeting to discuss possible measures and a block on flights could also be extended to other South American countries in a bid to stop its spread.
Prime Minister Boris Johnson has said he is "concerned" about the new variant and "extra measures" were being taken.
Arrivals from Brazil are currently required to self-isolate for 10 days.
During a two-hour appearance in front of the Commons Home Affairs Committee on Wednesday Mr Johnson stopped short of promising a ban on travel from Brazil.
"We already have tough measures ... to protect this country from new infections coming in from abroad," he said.
"We are taking steps to do that in respect of the Brazilian variant."
Prof Susan Hopkins, who is Strategic Response Director for Covid-19 with Public Health England, told BBC Breakfast experts were looking at the Brazilian variant and needed to grow the virus in the UK in order to perform laboratory experiments.
"So we need to understand the biology of these [new strains], as well as understanding mutations," she said.
"We will be watching them all to make sure that they can't escape your immune response, which is the key thing that we're looking at the moment."
Transport Secretary Grant Shapps said the new rules had been delayed from Friday "to give international arrivals time to prepare".
Yvette Cooper, chairwoman of the Commons Home Affairs Committee, described the delay in introducing the new rules as "truly shocking".
Scotland is taking the same approach to international travellers but will implement the policy on Friday, while Wales and Northern Ireland are expected to announce their own plans in the coming days.