Tracing the origins of the latest case of coronavirus – the first to have been caught within the UK – will be “crucial” in preventing more extensive spread, experts have said.

Jonathan Ball, professor of molecular virology at the University of Nottingham, said UK transmission was “always a real possibility” and that with symptoms very similar to flu, it can be easy for Covid-19 to go under the radar.

The latest case was the 20th positive diagnosis in the UK and health officials said it was not yet clear if the virus had been passed on “directly or indirectly” from somebody who had recently travelled abroad.

All previous confirmed cases have been passed on overseas, in countries including France, Italy and Iran.

Prof Ball said: “This case – a person testing positive for novel coronavirus with no known link to an affected area or known case – marks a new chapter for the UK and it will be crucial to understand where the infection came from to try to prevent more extensive spread.

“This was always a concern – this is a virus that frequently causes symptoms very similar to mild flu or a common cold, and it’s easily transmitted from person to person.

“This means it can easily go under the radar.”

Dr Stephen Griffin, associate professor at the University of Leeds, said: “Whilst the first person-to-person transmission within the UK may come as a shock to many, it was really only a matter of time.

“What now becomes critically important is our ability to identify, isolate and care for infected individuals, and to trace their recent contacts.

“If localised outbreaks remain contained then it should be possible to limit the impact upon the UK. However, I suspect the frequency of small outbreaks might increase in coming weeks as the source countries of imported cases become more diverse.

“If we experience a burgeoning epidemic as seen in South Korea it will represent a significant challenge to our already stretched NHS and public health infrastructure.

“As directed by WHO, we should use this time window to invest and prepare for such a potential outbreak, whether it happens or not.”

Dr Michael Head, senior research fellow in global health at the University of Southampton, said it was “unsurprising” to see a case of human-to-human transmission in the UK.

He added: “There will be significant efforts to look at how this patient came to be infected, who is the index case in the UK and to see if any there are any other secondary cases.

“Though this is a notable development here in the UK, the overall risks to the public right now remain unchanged.”