Social isolation measures will need to be in place for most of a year at least in order to control the spread of the coronavirus outbreak, according to experts' advice to the Government.

Scientists also advised ministers that, while the severity of measures could alternate during the period, the "stricter" measures would need to be enforced for at least half of the year.

The Government published the advice on Friday - a day after Prime Minister Boris Johnson said he expects the tide to be turned in the fight against Covid-19 within 12 weeks.

York has been left deserted tourist attractions closed. Credit: PA

A report by the Scientific Pandemic Influenza Group on Modelling states: "It was agreed that the addition of both general social distancing and school closures to case isolation, household isolation and social distancing of vulnerable groups would be likely to control the epidemic when kept in place for a long period.

"It was agreed that a policy of alternating between periods of more and less strict social distancing measures could plausibly be effective at keeping the number of critical care cases within capacity.

"These would need to be in place for at least most of a year. Under such as policy, at least half of the year would be spent under the stricter social distancing measures."

The triggers for controls to be imposed or lifted could be set at a level of UK nations and regions, the advice states, suggesting that more stringent measures could be enforced in London, where the disease is spreading fastest.

Some gyms have shut off alternate machines to enforce social distancing. Credit: PA

The advice dated Monday says the measures that would need to stay for "a long period" would include general social distancing, school closures and household isolation.

Three days later, the PM told the nation: "I think, looking at it all, that we can turn the tide within the next 12 weeks and I'm absolutely confident that we can send coronavirus packing in this country."

The document also stresses the need for the general public to follow the advice on social distancing, saying critical care facilities will likely be "overwhelmed" unless all measures are taken.

But still the experts said it was "unclear" whether the steps introduced so far would "curtail the epidemic" by stopping its spread.

Separate advice from the Scientific Group on Behaviour and Communications detailed the weight of the pressure on the PM.They said that public disorder amid epidemics is "usually triggered by perceptions about the government response".

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However, they did agree that "large-scale rioting is unlikely" and that there is a greater chance of acts of altruism predominating, which they said ministers could "promote and guide".

One risk to order is from police actions being deemed excessive, with the experts advising that officers should take a role of "support rather than control".

To minimise the chances, ministers were told to "provide clear and transparent reasons for different strategies" with "clear expectations on how the response will develop".

A sense of collectivism should be fostered with messaging reinforcing a sense of community and that "we are all in this together", they advised.

People have been advised to make all but essential journeys. Credit: PA

However, the behavioural advisers warned that the household isolation advice and school closures will have greater impacts on poorer families.

"For poorer families, loss of income and increased household bills (heating, electricity, food delivery etc), will occur concurrently with loss of social services provided through schools (free school meals, after school clubs etc)," they said.

On social distancing, the advice suggested that the risk of infection from attending large events is generally no higher than smaller gatherings.

However, family gatherings are considered to be particularly high-risk as they bring people into closer contact - as do religious services with high physical contact.

"Smaller gatherings such as bars and nightclubs are higher risk as you can be in closer contact with others," the scientists said.

"Family gatherings are particularly high-risk as they bring people into closer contact. Similarly, religious services with a high level of physical contact would be higher risk.

"Some activities are higher risk because they are disproportionately depended (on) by older groups."