Travellers arriving in the UK will have to take a PCR test by the end of the second day, prime minister Boris Johnson announced on Saturday (27 November).
He also said travellers would have to self-isolate until they provide a negative result.
The move comes after South Africa, Botswana, Eswatini, Lesotho, Namibia, Zimbabwe, Angola, Malawi, Mozambique and Zambia were added to the UK’s red list due to fears over the new Omicron variant of Covid-19.
Spain, Morocco, Denmark, Switzerland and Japan have also reintroduced travel restrictions on UK arrivals.
The DfT said: "From 4am 30 November, lateral flow tests will not be accepted. You must arrange to take a PCR test before the end of day 2 after you arrive.
"You must self-isolate in your home or the place you are staying until you receive your test result.
"If your PCR test results are delayed, you must self-isolate until your test result is known or until day 14 after arrival, whichever is sooner."