Hundreds of British nationals brought home from China because of the coronavirus outbreak are expected to be quarantined at a secure NHS facility for a fortnight, it has emerged.

As the last British Airways flights from Beijing and Shanghai returned to the UK after the airline suspended operations in China, about 200 Britons in the vicinity of Wuhan were preparing to leave on an emergency chartered plane.

They will be asked to sign a contract confirming their willingness to spend a fortnight in quarantine before being allowed to board the special flight. The UK-bound flight was due to depart on Thursday morning but on the evening before it emerged it would be delayed as permission had not yet been granted by Chinese authorities.

A Foreign Office spokeswoman said: “We are doing everything we can to get British people in Wuhan safely back to the UK. A number of countries’ flights have been unable to take off as planned.

“We continue working urgently to organise a flight to the UK as soon as possible.

“We remain in close contact with the Chinese authorities and conversations are ongoing at all levels.”

Planners earlier looked at holding returnees at a hotel or military base. But, after an emergency Cobra meeting on Wednesday afternoon chaired by the health secretary, Matt Hancock, it is understood that they will be flown into RAF Brize Norton in Oxfordshire and taken to an NHS facility to be monitored and treated if symptoms develop.

As the scramble among foreign nationals to get out of China intensified, there was controversy over the rights of British families including Chinese passport-holders to leave the country together. Some dual nationals face being trapped in the Wuhan region, where the virus broke out, even as their loved ones go home.

After it emerged that China’s policy of not recognising dual nationality meant that some families would be separated, one married couple with a nine-year-old daughter who are trapped in the region said it was their “worst nightmare”.

The death toll from the virus has risen to 170, and the number of people infected now stands at 7,183 worldwide, including newly confirmed cases in countries including Finland, France, Australia and the UAE. That is more than the number of confirmed cases of Sars in mainland China during the outbreak in 2003.

The Department for Health and Social Care said 130 people in the UK had been tested for the virus and no one had yet been diagnosed with it.

Hancock sought to ease public concern about the spread of the disease by stating that those returning to Britain would be quarantined and receive medical attention. “We are working hard to get British nationals back from Wuhan,” he tweeted. “Public safety is the top priority. Anyone who returns from Wuhan will be safely isolated for 14 days, with all necessary medical attention.”

There were fears that some of those registered for the flight may not be able to make it to the airport. Robert Dowling, from Nottingham, said his 22-year-old son in Wuhan was due to get on the flight but lived on the other side of the city and, with Wuhan in lockdown, had no means of travel.

He said the Foreign Office was not helping Britons with their travel through Wuhan. “On the group chat [on social media between British nationals in Wuhan] this is a constant theme, with it sounds like quite a number of them not at all sure how they are going to get to the airport,” he said.

Nick House, a British national living in Wuhan with his Indonesian wife and two British children, told Sky News: “The man on the other end of the phone said: ‘Yes, you are on the list but unfortunately your wife probably won’t be able to get on the plane because she doesn’t have a visa at the moment.’ 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.”

On the question of the treatment of dual nationals, the prime minister’s press secretary said: “Our priority is to keep British nationals and their families together and we have urgently raised this with the Chinese authorities including through the foreign secretary speaking to his counterpart yesterday. It is Chinese policy that those with Chinese dual or mono-nationality cannot leave Wuhan through an assisted flight.”

The DHSC refused to comment on what legal powers the government might use to compel people to stay in isolation. Legislation allows local authorities to apply for orders to make people enter isolation to prevent the spread of disease.

Mark Harris, a professor of virology at the University of Leeds, broadly backed the quarantine strategy. “The plans for an organised quarantine of people evacuated from Wuhan makes much more sense than a proposal that people would quarantine themselves,” he said.

“There is now very good scientific evidence that the incubation period before symptoms appear can be as long as 14 days. In addition, there is some limited evidence of spread from people who are not yet showing symptoms. Both of these issues highlight the need for quarantine.”

Virgin Atlantic and Chinese carriers continued to operate flights to and from mainland China despite British Airways’ move to suspend planes in the wake of government travel advice.

The coronavirus is believed to have emerged from wild animals sold for food in the Wuhan seafood market, which has been closed. It has a fatality rate of about 2% and symptoms include a sore throat, fever and breathing difficulties.