Britain's government will require people entering England to present a negative COVID-19 test result on arrival, the government said on Friday (December 8).
The new measure will start next week to protect against new strains of the coronavirus from other countries.
Passengers arriving by boat, plane or train will have to take a test up to 72 hours before departing for England.
It mirrors measures taken by many other countries around the world.
British Transport Secretary Grant Shapps said on Friday there are concerns about how effective the COVID-19 vaccines might be against a highly transmissible variant of the coronavirus discovered in South Africa.
On Thursday, Britain said it would extend a ban on travelers entering England from South Africa to other southern African countries to prevent the spread of the variant identified in South Africa.
The British government ordered a new lockdown for England this week after a surge in cases linked to a new variant of the coronavirus believed to have originated in the country.
On Friday a study by U.S. drugmaker Pfizer said its vaccine with BioNTech appeared to work against a key mutation in the new variants of the coronavirus discovered in both the UK and South Africa.
The not-yet peer reviewed study indicated the vaccine was effective in neutralizing virus with the so-called N501Y mutation of the spike protein.
Its findings are limited, because it does not look at the full set of mutations found in either of the new variants of the rapidly spreading virus.