Italy and Austria have joined the Netherlands and Belgium in banning air travel from the UK due to concerns over the new strain of coronavirus.
The Netherlands was the first country to ban flights after health authorities confirmed at least one case of the same variant that has prompted the UK to tighghten lockdown rules.
Belgium then stopped flights and halted rail connections.
Italy announced their measures shortly after midday on Sunday, but it is not known how long they will be in place for.
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The Dutch measures are expected to last until at least the new year.
Austria said it would also halt flights from the UK but there were no immediate details on the timing of the ban, news agency APA reported.
Germany is also understood to be considering action, with a German government official telling the dpa news agency that restrictions on flights from Britain are a “serious option”.
Belgian Prime Minister Alexander De Croo said on Sunday he was issuing the order for 24 hours starting at midnight “out of precaution,” and that he hoped to have more clarity on Tuesday.
The World Health Organisation (WHO) has announced it was in “close contact” with the UK about the new mutation of the virus, and they have both shared information and results of analysis about the novel outbreak.
England’s chief medical officer, Professor Chris Whitty, said the UK had told the international healthcare body about the development after modelling showed a rapid spread of the new variant in southeast England.
Maria Van Kerkhove, from the WHO, said earlier this week the strain bore similarities to a variant initially discovered in mink in Europe.
A new report published by the organisation has called for “enhanced” surveillance worldwide in light of the recent developments.
The Dutch health ministry said the case there had been identified at the beginning of December and is being investigated.
Meanwhile, it said “any introduction of this virus strain from the United Kingdom should be limited as much as possible by limiting or controlling passenger movements from the United Kingdom as much as possible”.
The air traffic ban for passengers from the UK began at 6am today and will apply until 1 January at the latest.
The Dutch government said: “The cabinet is closely monitoring the developments of the COVID-19 virus abroad and is investigating the possibilities for additional measures for other modes of transport.
“In the coming days, it will, in close collaboration with other EU member states, look into the possibilities of further restricting imports of the virus from the United Kingdom.”
The new strain of coronavirus – known as VUI-202012/01 – is believed to spread more quickly than the original strain and is thought to be the reason for rapidly-rising infection rates in London and the South East.
Boris Johnson warned on Saturday that the new strain might be “up to 70% more transmissible”.
“While we are fairly certain the variant is transmitted more quickly, there is no evidence to suggest that it is more lethal or causes more severe illness,” the prime minister said.
“Equally there is no evidence to suggest the vaccine will be any less effective against the new variant.”
Sir Patrick Vallance, the UK government’s chief scientific adviser, said the new variant is thought to have emerged in the UK in mid-September.
By December, it was responsible for more than 60% of infections in London, he said.
Mr Johnson announced that millions of people in London and many parts of the South East will not be allowed to mix with other households at Christmas as they are now under a new Tier 4 level of restrictions.