An eight-month-old baby has "all the coronavirus symptoms", potentially making him the youngest Briton infected in the epidemic.
The little tot's dad said the family are "in hell, completely petrified" and fears his four-year-old daughter also has the deadly disease as a result.
The baby boy and his mum are now in quarantine in their own home in Worthing, West Sussex, after coming into contact with a GP who has tested positive.
Speaking to the Telegraph, the dad, who did not wish to be named, said: "We're in hell, completely petrified. My ex-partner keeps breaking down in tears.
“We’re staying in the house and giving the kids Calpol and paracetamol, but nothing's working.
“My little boy has haemophilia and a lung condition, so he’s already poorly."
The infected GP came into contact with 12 patients last week at Worthing Hospital who health officials are desperately trying to trace, as they attempt to curb the spread of the disease in the UK.
Hours earlier London's first case was confirmed yesterday after a woman flew from China to the capital city before testing positive in the afternoon.
A total of nine people have the virus in the UK and officials are attempting to contact everyone the woman has been in the company of since her return.
Professor Chris Whitty, Chief Medical Officer for England said: “One further patient in England has tested positive for novel coronavirus (COVID-19), bringing the total number of cases in the UK to nine.
“This virus was passed on in China and the patient has now been transferred to a specialist NHS centre at Guy’s and St Thomas’ in London.”
Experts believe London is at greater risk than any other place in Europe because of the vast number of Chinese visitors who come each year, including 142,000 between January and March.
While the extensive transport network and huge population mean tracking down potential victims is next to impossible to do with any urgency.
Dr Michael Head, Senior Research Fellow in Global Health, University of Southampton, said: “If confirmed, it is not surprising that London has seen its first case of the coronavirus.
“It’s a city of over 10 million people with several major international airports.
“Both London and the rest of the UK can expect to see more cases, though hopefully these will continue to be isolated cases and seen in small numbers,” he added.
A total of 1,759 people have been tested in the UK, with those infected include one in London, five in Brighton, two in York and another one in an undisclosed location.
A dozen schools in Sussex are in infection alert, with staff and children told to self-quarantine at home by Public Health England as the county has the highest number of infected.
Brighton became the epicenter of the flu-like ailment in the UK thanks to Stephen Walsh, a 53-year-old businessman and scout leader who brought it back from Singapore last month.
The 'super-spreader' is believed to have unwittingly spread the virus to numerous people, in part due to a trip to the French Alps on his way back to the UK in which two Brit GPs among others caught it from him.
A neighbour of Mr Walsh said he is concerned that he will be used as a scapegoat for the spread of the virus in Britain.
Ian Henshall, 59, said: “I’ve spoken to his wife Cathy directly and to Steve by email and they are absolutely terrified of being made scapegoats for all this which would be totally unfair.”
Mr Walsh was discharged from an isolation unit at St Thomas' Hospital yesterday.
The sales executive said: “I’m happy to be home and feeling well.
"I want to give a big thank you to the NHS who have been great throughout and my thoughts are with everyone around the world who continues to be affected by the virus.
"It’s good to be back with my family and I would ask you please to respect our privacy from this point on”.
County Oak Medical Centre in Brighton, East Sussex, was closed while staff in hazmat suits deep cleaned the surgery, while a surgery in the city — the Lions Dene surgery — linked to super-spreader Mr Walsh, also closed.
An alleged Brit drug lord, is at the centre of a coronavirus outbreak at HMP Bullingdon after being arrested on suspicion of dealing class A drugs in Thailand and extradited back to the UK to stand trial.
Mark Rumble, 31, was brought back on January 27 and collapsed in his cell just days later resulting in a whole block being shutdown.
Professor Neil Ferguson, from the MRC Centre for Global Infectious Disease Analysis at Imperial College, London, told the BBC Radio 4 Today programme the world was "in the early phases of a global pandemic at the moment".
He said: "The fact we have only recorded eight cases in the UK is because our surveillance is focused on travellers.
"We think probably we are picking up maybe one in three cases coming into the country at the current time.
"We will know more in the next few weeks.
"Surveillance has started across the UK in hospitals of pneumonia cases. That will give us a proper picture."
Meanwhile, with nearly 50,000 infected as health chiefs introduce new clinical methods.
Authorities said the figure rose by 242 on Wednesday to 1,310.
A further 14,840 cases had been detected in Hubei, the epicentre of the outbreak, taking the total in the province to 48,206, officials confirmed.
The new deaths were more than twice the prior provincial daily record of 103 set on Monday.
