Two cases of coronavirus have been confirmed by British health officials as the country prepared a large-scale quarantine operation for scores of citizens evacuated from the Chinese city of Wuhan on Friday.
Professor Chris Whitty, chief medical officer for England, said on Friday: "We can confirm that two patients in England, who are members of the same family, have tested positive for coronavirus.
"The patients are receiving specialist NHS care, and we are using tried and tested infection control procedures to prevent further spread of the virus."
The two cases are the first instances of the virus being identified in the UK, making it the 23rd country or territory outside of China to have confirmed coronavirus cases.
The Department of Health declined to say where in England the patients were from.
Before the cases were confirmed, more than 160 people were tested for the virus in the UK, but all the tests came out as negative.
More than 80 Britons are on an evacuation flight from the Chinese city of Wuhan, where the outbreak first was reported, and are due to land on Friday afternoon. The flight is expected to arrive at the Brize Norton RAF base in Oxfordshire around 1pm, the Britain's foreign office said in a statement.
Four British chief medical officers, including Mr Whitty, have increased the risk level of coronavirus from low to moderate, adding they “do not think the risk to individuals in the UK has changed” but that the government should “plan for all eventualities”.
Speaking on the two cases, Mr Whitty added: "The NHS is extremely well-prepared and used to managing infections and we are already working rapidly to identify any contacts the patients had, to prevent further spread.
"We have been preparing for UK cases of novel coronavirus and we have robust infection control measures in place to respond immediately.
"We are continuing to work closely with the World Health Organisation and the international community as the outbreak in China develops to ensure we are ready for all eventualities."
Since the first deaths from the infection were announced earlier this month, there has been a dramatic increase in face masks being bought globally as some think they may help stop the virus from spreading.
The outbreak, which has killed at least 213 people in China – mostly in Hubei province – has almost 10,000 cases nationally.
Wynne Lloyd-Williams, a managing director of the Wales-based medical supplies firm Cymru Healthcare, said it had sold its entire stock of 500 masks to a Chinese buyer from Leicestershire.
"We've seen a dramatic increase in demand," he told the BBC.
"This is unusual. They are not a significant product, but people now are thinking 'should we purchase them?'"
But Public Health Wales has said there is "insufficient evidence" to suggest you will benefit from wearing a mask.