Denmark has been removed from the UK’s coronavirus travel corridors list.
Those arriving in the UK from the country after 4 am on Friday now must self-isolate for 14 days.
It comes after health authorities in Denmark found a mutated form of Covid that can pass to humans, present in its mink farms.
Transport Secretary Grant Shapps said: “I understand that this will be concerning for both people currently in Denmark and the wider UK public, which is why we have moved quickly to protect our country and prevent the spread of the virus to the UK.
“Health authorities in Denmark have reported widespread outbreaks of coronavirus in mink farms, with a variant strain of the virus spreading to some local communities.
“The chief medical officer has therefore recommended that, as a precautionary measure, all those returning from Denmark should self-isolate for 14 days.
“People currently in Denmark may finish their trip, follow the local rules, and check the Foreign, Commonwealth and Development Office travel advice pages on GOV.UK for further information.”
Under England’s new lockdown measures that came into force on Thursday, leaving home to travel for holidays is no longer allowed.
Denmark was only added to the quarantine-free list on October 25.
The move comes just hours after Germany and Sweden were removed from the list, with people traveling to the UK from those destinations to quarantine for two weeks if they arrive after 4 am on Saturday.
Germany’s seven-day rate of coronavirus cases per 100,000 people reached 140 after nearly 20,000 cases were reported on Wednesday.
The rate for Sweden is 190.
Figures have been calculated based on data collected by the European Centre for Disease Prevention and Control.
The Government is believed to be using a rate of 100 as the threshold above which it considers triggering quarantine conditions. This is up from 20 in recent months.
The UK’s own rate is 235.
Mr. Shapps has launched a task force to develop methods of reducing the 14-day self-isolation period for people arriving from non-exempt locations.
He said the Government was considering a “test and release regime” which would still involve a quarantine period of at least a week.