European Union officials will discuss later a co-ordinated response to a new, more infectious coronavirus variant in the UK, which has led many countries to impose travel bans.
Germany, France and Italy are among those to suspend flights from the UK. Outbound train services through the Channel Tunnel have also been halted.
Canada is also blocking UK flights.
Health officials say the new variant is up to 70% more transmissible, but there is no evidence that it is more deadly.
There is also no proof to suggest that it reacts differently to vaccines.
UK Health Secretary Matt Hancock said the new variant was “getting out of control”, while Denmark, Italy and the Netherlands announced they had already detected it.
The European Council meeting of government representatives is expected to take place at 10:00 GMT. The speed at which governments have announced their bans on travellers from the UK shows the scale of the alarm, the BBC’s Gavin Lee in Brussels reports.
Also on Monday, the EU’s medicines regulator is expected to recommend approving the Pfizer-BioNTech coronavirus vaccine for use in all 27 states.
The European Medicines Agency (EMA) is meeting a week early to decide on the vaccine which is already being administered in the UK and in the US.
If it gives the green light, official approval from the European Commission is expected to follow on Wednesday and vaccine distribution may begin in some EU states as early as Sunday.
Which countries have acted and how?
France suspended all travel links, including freight lorries, with the UK for 48 hours from midnight (23:00 GMT) on Sunday. Thousands of lorries move between the countries every day.
Eurotunnel said it would suspend access to its Folkestone terminal for traffic heading to Calais. People booked to travel on Monday can get a refund. Trains will still run from Calais to Folkestone.
The ferry terminal at Dover is now closed for all accompanied traffic leaving the UK until further notice because of the French restrictions. UK Prime Minister Boris Johnson will chair a Cobra emergency response meeting to discuss the issue on Monday.
Other countries took different action in response to the new virus variant:
Denmark suspended flights from the UK for 48 hours beginning at 09:00 GMT on Monday.
The Netherlands is banning all passenger flights from the UK until 1 January “at the latest”. Ferry passengers arriving from the UK will also be barred, although freight will continue
In the Republic of Ireland, flights arriving from Britain are banned for 48 hours at least from midnight on Sunday and people have been asked not to “travel to Ireland, by air or sea”. Ferry crossings for freight will continue
In Germany, planes from the UK have not been allowed to land since midnight on Sunday, although cargo is exempt
Belgium halted flights and trains from the UK from midnight for at least 24 hours
Italy has blocked all flights from the UK until 6 January
Turkey has temporarily banned all flights from the UK as has Switzerland
Austria will ban flights from the UK from 23:00 GMT on Monday and anyone arriving in the country before that point must quarantine for 10 days
Bulgaria has suspended flights to and from the UK from midnight with the ban to continue until 31 January
Canada has suspended entry of all passenger flights from the UK for 72 hours, effective from midnight (05:00 GMT). Passengers who arrived in Canada from the UK on Sunday would be “subject to secondary screening and enhanced measures, including increased scrutiny of quarantine plans”, it said.
India is suspending flights from the UK from 23:59 (18:29 GMT) on Tuesday until 31 December