People wearing face masks in public will become the new norm, a coronavirus expert has said.

Dr David Nabarro, the World Health Organisation's (WHO) coronavirus special envoy, said he believed people wearing some form of facial protection outdoors will become commonplace, if only for reassurance.

Speaking to BBC Radio 4's Today programme, Dr Nabarro said societies must adapt and "learn to live with the new reality of life with Covid-19" as the virus is likely to survive at varying levels within populations for some time.

"This virus isn't going to go away and we don't know whether the people who've had the virus stay immune afterwards and we don't know when we'll have a vaccine.

"So what we're saying is get societies defended. Yes, we will have to wear masks, yes, there will have to be more physical distancing, yes, we must protect the vulnerable," he said.

Acknowledging the worldwide shortage of face masks, Dr Nabarro said they should first go to health workers as a priority, before they are given to people with coronavirus symptoms and those around them, and then people working in close contact with others, such as cashiers and hairdressers.

"For the wider population, we probably won't be able to ensure everybody quickly can access the good masks, the N95 masks, but then some form of facial protection I'm sure is going to become the norm - not least to give people reassurance," he said.

"I don't really like somebody in my role saying this is the advice, it's up to national governments, but I think it will come because of what I'm calling being Covid-ready, learning to live with Covid.," he added.

"It's a revolution like when it was discovered that dirty water bore cholera in 1850, or like 25 years ago when we all learned about HIV/Aids and its relationship with sex. We changed and we adapted, we learned how to live with these new realities."

Dr Nabarro said there would need to be evidence of the whole of society taking coronavirus symptoms seriously when they prepare for the lockdown to be lifted.

He said: "The most important thing to do is to isolate yourself when you have symptoms, and make sure all those with whom you've been in contact recently isolate themselves as well.

"That's what's been done really successfully in Germany, we believe, and it's that habit.

"It's a habit, I want to stress this, that has to come in to the whole of society... of really taking these symptoms, even mild symptoms, seriously and making sure you get out of everybody's way."

Dr Nabarro also warned against the dangers of wet markets, as well as killing and eating wild animals, after wet markets reopened in the Chinese city of Wuhan, where the Covid-19 outbreak began.

He said: "There are real dangers in these kinds of environments of pathogens hopping from animals to humans.

"Seventy-five per cent of emerging infections come from the animal kingdom, so we really do plead with governments and plead with just about everybody else to be respectful."