All travellers to England from overseas will need to test negative for coronavirus before they are allowed to enter the country, the government has announced.
The test will need to be taken up to 72 hours before their departure – and failure to comply will result in an immediate £500 fine.
Arrivals by boat, plane and train are covered by the new regulations, which also apply to UK nationals.
The Department for Transport hopes the policy will help prevent the spread of new variants of COVID-19, such as those found in Denmark and South Africa.
Ministers have long faced calls to strengthen border measures with pre-arrival testing, which is already in place in many countries around the world.
Regardless of their test result, all passengers arriving from countries not on the government’s travel corridor list will still be required to self-isolate for 10 days.
They will have the option to reduce their quarantine period to as little as five days by paying for another test on or after the fifth full day since travelling to England.
Arrivals will also need to fill in a Passenger Locator Form and abide by the current lockdown restrictions.
Transport Secretary Grant Shapps said: “We already have significant measures in place to prevent imported cases of COVID-19, but with new strains of the virus developing internationally we must take further precautions.
“Taken together with the existing mandatory self-isolation period for passengers returning from high-risk countries, pre-departure tests will provide a further line of defence – helping us control the virus as we roll out the vaccine at pace over the coming weeks.”
From next week, Border Force officials will check passengers’ test results to ensure they are complying with the new rules.
There will be a limited number of exemptions to the new requirements – including for hauliers, children under 11, crews and for those who travelling from countries without the infrastructure available to deliver the tests.
There will also be no need for pre-departure testing for arrivals from the Common Travel Area with Ireland.
The new rules currently only apply to England, although the Department for Transport is working with the devolved administrations in Scotland, Wales and Northern Ireland to roll our similar measures.
Nick Thomas-Symonds MP, Labour’s shadow home secretary, said the measures were a “necessary step”.
However, he added: “Labour has been calling for a comprehensive strategy on testing for international travel since April. Instead, the government has been lurching from one crisis to another.
“In that time they have lost control of the virus and risked leaving the nation’s doors unlocked against the possibility of different strains of the virus entering the country from across the world.”
Tim Alderslade, chief executive of the industry body Airlines UK, said: “We recognise the government’s need to act now and support the introduction of pre-departure testing in order to keep the country safe and borders open.
“However, this should be a short-term, emergency measure only and once the rollout of the vaccine accelerates, the focus must be on returning travel to normal as quickly as possible in order to support the UK’s economic recovery.
“This includes removing the need to quarantine or test as the UK population is vaccinated and the virus is brought under control at home and abroad.”
Meanwhile, the French government has decided to keep the current testing arrangements for lorry drivers crossing the Channel.
Last month, France dramatically shut its border to arrivals from Britain – due to fears of the new COVID variant in the UK – with the resulting chaos causing huge queues of hauliers around motorways in Kent.
A deal to reopen the border between the two countries to hauliers and some passengers – if they test negative for COVID – was subsequently reached.
And, following a review of the measures, the French government on Thursday decided to keep the restrictions in place.