Strict social distancing measures may need to remain in place until the autumn to have the required impact in controlling the Covid-19 epidemic in the UK, according to government documents that reveal the thinking behind its approach to the crisis.

The documents, published online on Friday, give an extraordinary insight into the projected toll of the pandemic, the tactics that government advisers believe will be most effective in containing the spread of the virus and how messaging has been carefully framed to so the public accepts the need for unprecedented changes to daily life.

In a consensus statement on the overall strategy being deployed, the government’s scientific advisory group for emergencies (SAGE) suggests the UK would need to alternate between “periods of more and less strict social distancing measures” to have a plausible chance of keeping the number of critical care cases within capacity. “These would need to be in place for at least most of a year,” it concludes.

Quick guide What are coronavirus symptoms and should I go to a doctor? Show Hide What is Covid-19? Covid-19 is caused by a member of the coronavirus family that has never been encountered before. Like other coronaviruses, it has come from animals. The World Health Organization (WHO) has declared it a pandemic. What are the symptoms this coronavirus causes? According to the WHO, the most common symptoms of Covid-19 are fever, tiredness and a dry cough. Some patients may also have a runny nose, sore throat, nasal congestion and aches and pains or diarrhoea. Some people report losing their sense of taste and/or smell. About 80% of people who get Covid-19 experience a mild case – about as serious as a regular cold – and recover without needing any special treatment. About one in six people, the WHO says, become seriously ill. The elderly and people with underlying medical problems like high blood pressure, heart problems or diabetes, or chronic respiratory conditions, are at a greater risk of serious illness from Covid-19. In the UK, the National health Service (NHS) has identified the specific symptoms to look for as experiencing either: a high temperature - you feel hot to touch on your chest or back

a new continuous cough - this means you’ve started coughing repeatedly As this is viral pneumonia, antibiotics are of no use. The antiviral drugs we have against flu will not work, and there is currently no vaccine. Recovery depends on the strength of the immune system. Should I go to the doctor if I have a cough? Medical advice varies around the world - with many countries imposing travel bans and lockdowns to try and prevent the spread of the virus. In many place people are being told to stay at home rather than visit a doctor of hospital in person. Check with your local authorities. In the UK, NHS advice is that anyone with symptoms should stay at home for at least 7 days. If you live with other people, they should stay at home for at least 14 days, to avoid spreading the infection outside the home.

The advisory group also stresses the need to promote a sense of collectivism in a modern-day spin on “Keep Calm and Carry On”. “All messaging should reinforce a sense of community, that ‘we are all in this together’. This will avoid increasing tensions between different groups,” the documents say.

In papers that date from mid-February to the present, the group also considers issues ranging from public disorder to the psychology of self-isolation and potential social impacts of school closures. One paper outlines the potential for unintended consequences and the need to be clear about the purpose of school closures to prevent children from continuing to mix or grandparents taking on childcare responsibilities. Some social and workplace norms will need to be rapidly overturned. For instance, for many healthcare workers it is the norm that people continue to work when unwell. “It will be important to make it socially unacceptable to attend work or school if unwell,” the documents say. “To avoid the risk of stigma, ‘voluntary quarantine’ should be portrayed as an act of altruistic civic duty.”

An assessment of the chances of public disorder, drawn up in February, concluded that while “large-scale rioting” seemed unlikely, any disorderwas likely to be generated by anger at the government’s response rather than the direct effects of the pandemic.

One 12 March paper on public expectations about measures to stop public gatherings noted there was general support for the move, especially as people could see this happening abroad – and that if policy was not properly explained, people might not trust the government, potentially increasing the risk of disorder.

“Acting in a way that does not meet expectations poses a risk that a section of the public will view government actions as incompetent or not in the public’s best interests,” it says. “It may also be taken as signifying that the situation is not expected to be severe for the UK. This could have knock-on implications for public attitudes to other recommendations made by government.”

It adds that “the risk of public disorder would be higher if there was a perception that the government’s response was not competent”.

Other issues that could cause tensions, it says, include a possible lack of certain goods such as hand sanitisers, not enough police officers because of sickness, and police efforts seen as unfair, for example limiting access to food or healthcare.

Particularly, a lack of police numbers “could lead to a rise in opportunistic crime by those who are already antagonistic towards the police”, the paper says.

There is also more detail on what the government’s advisers expect to see as case numbers rise and how effective they expect various measures to be in reducing and delaying the epidemic’s peak. They estimate that about 8% of those infected will be admitted to hospital, including 44% of those aged over 80. Of those admitted, 12% are likely to die.

Social distancing, if enacted early and people are compliant, could reduce the peak by 50-60% and, combined with other measures, lead to a 30-45% reduction in deaths. Quarantining people with symptoms could make a 20% difference to the peak and closing schools could reduce the peak by 10-30%. There is expected to be a two to three-week delay between measures being put into place and their impact being felt in intensive care units.