All Brits left stranded in the coronavirus-hit Chinese city of Wuhan are expected to be flown home as early as Thursday.
But they are being warned it "may happen quickly and with short notice".
And one Brit has claimed her Chinese husband is not being allowed to come back to the UK with her, despite having a UK visa.
People are being urged to contact the British consulate before 11am on Wednesday if they wish to leave.
The Foreign Office has yet to confirm details, but a Brit working as a teacher in Wuhan city said that UK citizens stuck in Wuhan and the surrounding province of Hubei were being given details of forthcoming flights.
The British embassy in Beijing has warned transport to get UK citizens out may be sudden and Brits need to make contact as soon as possible.
The British teacher living in Wuhan, who asked not to be named, told PA she had been in contact with the British authorities who informed her that while she could return to the UK, her husband, who has a UK visa, would not be allowed to as he was a Chinese national.
It is understood that this was a result of restrictions imposed by China, rather than the UK.
As a result, she decided that she would remain in China with her husband.
She said: "It's what we were expecting to be honest, as we'd heard that it was like that for the American flight out. We had hoped it would be different, but oh well.
"If the situation stays as it is, or improves, then we're fine. We just hope it won't get any more serious."
She added that a number of other Britons she was in contact with had arranged to return home, with some scheduled on a flight at 7am on Thursday.
The news comes as almost 100 people in the UK have tested negative for coronavirus.
The Department of Health and Social Care said 97 people have been given the all-clear for the virus, although scientists predict it may have entered the country.
Earlier, Transport Secretary Grant Shapps said the Government was "working on" how to bring people home from the Chinese city.
He told BBC Breakfast: "For anybody who is there, one of the issues we have, working with our partners internationally on this, is actually identifying how many British citizens there are in Wuhan.
"One of the things we're asking people to do is to contact the consulate there to make them aware. People have started to do that.
"We are working on arrangements as well."
Officials estimate up to 200 citizens currently there will want to return to the UK.
Hubei province has been on lockdown for several days as China seeks to contain the illness, as have other parts of China.
Hong Kong also said on Tuesday it would "temporarily" close some of its borders with mainland China and stop issuing travel permits to mainland Chinese tourists.
More than 100 people have now died in the country, with confirmed infections surging to more than 4,500.
It comes as the UK expert developing a vaccine against coronavirus said it has a "very good chance" of being effective.
Professor Robin Shattock, head of mucosal infection and immunity at Imperial College London, told PA he plans to start testing the vaccine on animals by the middle of February, with human studies in the summer if enough funding is secured.
He warned there could be a second wave of coronavirus next winter across the globe.
On Monday, Health Secretary Matt Hancock called for people who have returned from Wuhan to "self-isolate" even if they have no symptoms.
He said officials could not be 100% certain the virus is not spread by people who are not displaying symptoms.
The move means more than 1,400 people who have returned from Wuhan since January 10 should isolate themselves for 14 days from the date of leaving China.
Meanwhile, reports from Japan and Germany on Tuesday suggested cases of coronavirus in people with no history of travel to Wuhan.
Scientists are also working on emerging evidence which suggests the virus can be spread by people before they even develop symptoms.
This could hamper efforts to contain the virus as people who have no indication they are ill go about their usual daily lives.