Eighty-three Britons and 27 foreign nationals who were trapped in Wuhan – the Chinese city at the centre of the coronavirus outbreak – are on a flight back to the UK.
The Foreign Office said medics are also on the flight, which is due to land at RAF Brize Norton at 13:00 GMT.
On arrival, the UK passengers will be taken to Arrowe Park Hospital on the Wirral and quarantined for two weeks.
The 27 foreign nationals – thought to be EU citizens – will fly on to Spain.
Foreign Secretary Dominic Raab described the news as “welcome”.
“We know how distressing the situation has been for those waiting to leave,” he said. “We have been working round the clock to clear the way for a safe departure.”
The flight was delayed by around three hours to allow as many UK and EU citizens as possible to get to the airport on time, amid a suspension of the city’s public transport.
The government initially estimated up to 150 Britons would be on the flight.
Meanwhile, Virgin Atlantic said it has suspended its flights to Shanghai for two weeks from 1 February, urging affected customers to contact them to receive a refund.
It follows British Airways’ decision to extend its cancellation of services to mainland China until 29 February.
The UK-bound flight comes hours after the World Health Organization (WHO) declared an international public health emergency over the outbreak.
The virus has caused 213 deaths in China – where there are now 9,962 confirmed cases – and spread to 18 other countries.
As of Wednesday, 161 tests had been carried out on people across the UK – all with negative results.
The UK’s four chief medical officers have said they are raising the risk level from low to moderate.
“This does not mean we think the risk to individuals in the UK has changed at this stage, but that government should plan for all eventualities,” a joint statement said.
They added that it was “likely” there would be “individual” cases of coronavirus in the UK.
Scotland’s chief medical officer said a case of coronavirus was “highly likely” to be detected in the country in the coming days.
But they said they were confident the heath services would be able to protect the public and provide high quality care.
Passengers flying from Wuhan are being accompanied by a team of Ministry of Defence medics.
Downing Street had been pressing Beijing to allow spouses or partners of UK nationals to travel on the Wuhan flight, after several Britons said family members with Chinese citizenship were not being permitted to travel by local authorities.
Wirral West MP Margaret Greenwood said she was told by Health Secretary Matt Hancock that the government did not think any of the people being flown back from Wuhan would be carrying the virus.
They will be put in “supported isolation” for 14 days with “all necessary medical attention”, a Downing Street spokesman said.
Most cases of coronavirus have emerged in people who have travelled from Wuhan.
However, there have been eight cases of human-to-human infection – in Germany, Japan, Vietnam and the United States.
The new virus has now infected more people in China than fell ill during the 2002-2003 severe acute respiratory syndrome (Sars) outbreak. The number of cases has jumped to 9,962, country’s National Health Commission said, surpassing the 5,327 people diagnosed with Sars.
However, the death toll is lower than the 348 people who died in China from Sars.
How deadly is coronavirus?
It is a basic question, but the answer is elusive.
It is far too simplistic to take the 213 deaths and the 9,962 cases and come up with a death rate of 2%.
We are in the middle of the outbreak and thousands of those patients are still being treated. We don’t know if they will live or die, so they can’t be used in these calculations.
We also don’t know how many mild and undetected cases are out there.
Also, the deadliness of the new virus is only one component of its threat.
Flu kills hundreds of thousands of people each year, not because it is super-deadly, but because it is able to infect so many people.