Britons returning from coronavirus-hit Wuhan in China will be put in quarantine for 14 days.
Officials are looking at taking passengers to a military base once they arrive home, the Department of Health said.
A flight is due to leave Wuhan in China on Thursday. It will carry passengers from Wuhan city and those from Hubei province who want to return to the UK.
Health Secretary Matt Hancock will also chair a meeting of the Government’s Cobra emergency committee on Wednesday, Downing Street said.
A source said: “We are expecting about 200 British nationals to be on board, there is capacity on the flight for everybody.
“On arrival passengers will be safely isolated for two weeks with all necessary medical attention.”
Number 10 refused to confirm where the Britons would be taken following the civilian charter flight to airlift them from the region.
Mr Hancock tweeted: “We are working hard to get British nationals back from Wuhan. Public safety is the top priority.
“Anyone who returns from Wuhan will be safely isolated for 14 days, with all necessary medical attention.”
Previous advice from Public Health England (PHE) was for those returning to stay at home for 14 days.
But Britons due to board the flight back from Wuhan said they had been told by authorities to make their own way through the city to Wuhan airport, and once they land on British soil they are expected to make their own way home, potentially coming into contact with hundreds of people on the way.
Experts in China have said there is evidence that people could transmit the virus without showing any symptoms, although UK experts think the risk is low.
“She is relieved, so am I, but she’s frustrated with the restrictions being put in place. She can only take 15kg of hand luggage and she came here with about 30kg of stuff.”
The family has not been given exact timings for the flight or details of which London airport Mrs Theobold will arrive at.
Mr Lambert has decided not to return, and will stay in Wuhan, but said his grandmother had been told previously she would have to get from London to Lancaster on her own.
“I won’t leave without my wife, so essentially the Government are leaving three British people here for the sake of one seat on a plane.”
It said that while China was doing all it can to contain the new coronavirus, its medical team had advised that “no-one should be going ahead with any major gathering that can be postponed”.
The Foreign Office updated its advice on Tuesday to warn against all but essential travel to mainland China, saying it may become more difficult for British nationals in other provinces to leave.
On Wednesday, British Airways announced it was suspending all flights to and from mainland China with immediate effect.
The airline, which operates daily flights to Shanghai and Beijing from Heathrow, said: “We apologise to customers for the inconvenience, but the safety of our customers and crew is always our priority.
Virgin Atlantic said its flights between Heathrow and Shanghai will continue to operate as scheduled, although passengers are able to re-book or obtain a refund free of charge.
Chinese airlines which serve UK airports such as Heathrow, Gatwick and Manchester – including Air China, China Southern Airlines, China Eastern Airlines, Hainan Airlines and Tianjin Airlines – all appear to be operating flights as normal.
Lecturer Yvonne Griffiths, who is in a hotel in Wuhan, said she received news in the early hours of Wednesday morning that there was to be a flight from Wuhan to the UK.
She told BBC Breakfast that Stansted is a possible destination but that has not been confirmed, and timings had not been been firmed up either.
“We’ve to be on stand-by so that we can go to the airport very early,” she said.
“We’ve to be there six to seven hours before the flight leaves, and we would have a screening from some health people here in Wuhan, and if we are not showing any symptoms then we’ll be able to board that plane.
“It has been frustrating up until today. I think the lack of certainty about the time of this flight isn’t so worrying as long as we know that it’s going to happen.
“Prior to that, we had quite a long period of silence from the UK Government about whether there was going to be any contingency plan to get people home.”
Four cases have been confirmed in Germany, making it the second European country to report cases after France.
In Australia, officials unveiled plans to evacuate its nationals from Wuhan and Hubei province, with plans to quarantine them in the Christmas Island immigration detention centre.
The World Health Organisation (WHO) said the latest indications are that one in five cases of coronavirus are leading to severe disease, such as pneumonia, or were causing death.
Following the latest Foreign Office travel advice, consumer group Which? said people with trips to China planned should be covered for cancellations by their travel insurance.