Passengers leaving for England and Scotland will soon need to provide a negative COVID-19 test result before their departure.
The measure will apply to all international passengers in a bid to help protect against new strains of coronavirus circulating internationally.
It will take effect from next week in England and Scotland has said it wants to introduce the restriction "as soon as possible".
UK Transport Secretary Grant Shapps has announced that from next week inbound passengers arriving by boat, plane or train will have to take a test in the 72 hours before departing for England, to help protect against the new strains of coronavirus such as those seen in Denmark and South Africa.
A negative pre-departure test reduces the risk of someone travelling whilst infectious, acting as another safeguard to prevent importing the virus, the government said.
Passengers arriving in England from countries that have been identified as high-risk by authorities must still self-isolate for 10 days regardless of their pre-departure test result.
"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," said Shapps.
Travellers will need to present proof of a negative COVID-19 test result to their carrier before boarding and the UK Border Force will conduct spot checks on arrival into England to ensure that passengers are fully compliant.
One-in-50 people in England had COVID-19 last week, according to new figures cited by UK PM Boris Johnson at a press conference on Tuesday.
The revelation came after the country posted a new daily high for COVID cases - 60,916. It's the first time the total has exceeded 60,000.
A new nationwide lockdown took effect at midnight on Tuesday amid the surging cases.
Chief Medical Officer for England, Prof Chris Whitty said on Tuesday the new variant identified in the UK was "taking off" in areas outside London and the South East, where it has been found to be prominent.
Johnson on Thursday said the UK intends to deploy hundreds of thousands of vaccines by next week and will inoculate 15 million people by February 15.
He told a televised press conference that the government planned to vaccinate people at nearly 1,500 locations around the country.
Vaccine supplies were “enough” for the country’s most vulnerable people, he added.
There were 1,162 deaths recorded in the previous 24 hours and 52,618 new cases of the virus reported in the same period.