Boris Johnson warns that thousands will catch coronavirus across Britain

Boris Johnson today conceded that thousands of cases of coronavirus can be expected in the UK, as the World Health Organisation warned that countries were facing “uncharted territory” in coping with the outbreak.

Mr Johnson said Britain “will face a challenge in the weeks, months ahead” as the government prepared to unveil its battle plan.

This will include emergency laws to enlist newly retired doctors and nurses and to allow higher staff-to-pupil ratios in schools.

Chancellor Rishi Sunak has also moved to reassure the financial markets. He said the Treasury “stands ready” to support the NHS, businesses and wider economy.

WHO director general Dr Tedros Adhanom Ghebreyesus said doctors had “never before seen a respiratory pathogen capable of community transmission which could also be contained within the right measures” but he stressed it was still possible to “push this virus back”.

Professor Paul Hunter, an adviser to the World Health Organisation and expert virologist who has studied the spread of diseases including Ebola, Sars and Zika virus for more than 20 years, said the coronavirus could potentially kill tens of thousands.

He said the elderly could be most at risk in the event of a major outbreak. ”My best guess would be similar to a bad flu year where we see up to 50,000 deaths. It is possible this would be more than that but not more than twice that. That’s my best judgement,” he said.

Professor Hunter, also part of the WHO research committee trying to defeat the outbreak​, said he “wouldn’t bet against the risk the NHS is overwhelmed”. He said the health service would be forced to ration access to beds.

He stressed the UK was not at this point yet but there were strong indications from Europe and other countries that the infection would become firmly established in the UK.

And yet less than 1 per cent of doctors, eight out of 1,600 polled, feel that the NHS is “well prepared” for the coronavirus, the Doctor’s Association UK said.

On Monday, the number of confirmed cases in the UK hit 39, while the global death toll from the disease passed 3,000. More than 80,000 people have been infected worldwide.

Prime minister Boris Johnson accepted there could be thousands of cases of the virus, telling the BBC: “You’ve got to consider the realistic possibility that there is now going to be a significant expansion in the number of cases.”

Mr Hunter, a professor of medicine at the University of East Anglia, said the spike in cases in France, Germany and Italy “means that in Europe it is starting to spread in a self-sustaining fashion”. He said: “We are not there yet in the UK, but I think it is inevitable. I can’t see how that won’t happen given what is happening in the rest of Europe.”

At the moment, anyone infected with the virus is taken to a special unit to prevent them infecting others. But Professor Hunter said as the outbreak develops a new approach would be needed.

“Once we get self-sustaining spread in the UK then the current strategy of containment becomes pointless. That is not going to stop the disease spreading, it’s not going to work.

“Public Health England want everyone who might be affected taken to hospital but if the disease is spreading in the community, the focus should shift to caring for the people who are most ill.”

He added: “I wouldn’t bet against the risk that the NHS is overwhelmed in terms of its critical care beds and in that situation you would see some type of rationing of access to those beds.

“I don’t think that’s inevitable but I wouldn’t bet against it. If you can get the delaying strategy right, it wouldn’t get to the point where the NHS collapses.”

But he admitted being “worried” about the virus and said it needed to be taken seriously, adding: “It is 10 to 20 times more lethal than influenza.”

He said the Department of Health and Social Care strategy to contain the virus and then to delay the outbreak into the spring and summer was the right approach. He added delaying the outbreak would mean “we don’t get quite as big a spike”, alleviating pressure on hospitals.

Professor Hunter said he believed the virus was here to stay and would become “seasonal” in nature.

“This is an educated guess but I think it will tail off in the summer and it will then come back again next winter with a second peak,” he said.

He reiterated government advice for people to wash their hands and to avoid touching their face.

In a large-scale outbreak, UK hospitals could be forced to discharge large numbers of patients into the community. The Queen’s Nursing Institute called on the government to activate “an army of former district nurses” to help keep vulnerable patients safe.

Dr Crystal Oldman, chief executive of the QNI, told The Independent many former nurses who had retired but kept their registration could be brought back.

“We have an army of nurses who are just retired and still on the register who will come back and help,” she said. “This is a crisis, nurses will always want to help in a crisis.”

The latest analysis from the World Health Organisation said among a sample of 44,672 patients in China with confirmed infection, most patients (80 per cent) experienced mild illness, while approximately 14 per cent experienced severe disease and 5 per cent were critically ill.

Severe illness is associated with being over 60 and having other underlying illnesses. Death rates are estimated to be 1 to 2 per cent.