Boris Johnson is poised to move Britain to a critical new phase of the coronavirus action plan on Thursday, paving the way for social distancing. The measures come the day after the UK recorded the biggest single-day increase in virus cases, and the number of associated deaths rose to eight.

The prime minister will chair a meeting of the Cobra emergency committee at lunchtime, and is expected to rubber-stamp a decision to move to from the “contain” phase to “delay”.

The change raises the prospect of measures such as home working, school closures, limits on gatherings, and a scaling back of non-urgent hospital, police and fire services.

The delay phase of the plan involves much of the same advice to people as the contain phase, including washing hands, quarantining, and testing.

The government’s coronavirus plan states that possible actions include “population distancing strategies such as school closures, encouraging greater home working, reducing the number of large-scale gatherings”.

It adds: “We would consider such measures in order to protect vulnerable individuals with underlying illnesses and thus at greater more at risk of becoming seriously affected by the disease. The effectiveness of these actions will need to be balanced against their impact on society.”

Ministers will hold cross-party talks with Labour on Thursday about the emergency legislation required to implement and enforce some of these measures. Matt Hancock, the health secretary, said the government hoped to pass the legislation next week.

Quick Guide What are coronavirus symptoms and should I go to a doctor? Show 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 number of coronavirus patients in the UK rose by 87 to 460 on Wednesday, the biggest daily increase to date, and deaths in the UK rose to eight.

Two patients in Dudley and Nuneaton, who were both aged over 70 and had underlying health conditions, died after contracting Covid-19, health officials said.

Earlier, the death was announced of a 53-year-old British woman in Bali, Indonesia, who was already critically ill when she was diagnosed. She is believed to be the youngest British victim and the second to die overseas from the virus.

The woman had been on a family holiday with her husband and four children at the island’s Four Seasons hotel. They arrived on 29 February and it was unclear where she contracted the virus. She first reported a fever on 3 March, health officials said.

“The patient had severe illnesses including diabetes, hypertension, hyperthyroid and lung disease,” said Achmad Yurianto, a spokesman for Indonesia’s virus response team. She was cremated in Bali at the family’s request. Her husband is under observation in hospital and her children are in quarantine, according to local reports.

In what is believed to be the first UK case in a care home, a staff member of a residential home for people with learning and physical disabilities in Desborough, Northamptonshire, was confirmed to have tested positive. The Heather Holmes facility cares provides accommodation for up 12 working-age adults.

The Office for National Statistics said a member of staff at its headquarters in Newport, south Wales, had tested positive, as Public Health Wales reported that cases in the country had increased by four to 19.

Barclays said an employee at its Canary Wharf office in London had tested positive and that it would deep-clean and disinfect the site.

The government’s expected move to the “delay” phase over coronavirus comes after Hancock was pressed by MPs in the Commons over the government’s handling of the outbreak.

The shadow health secretary, Jon Ashworth, asked Hancock to explain why the government had not already shifted to delay. Pointing to concerns raised by the editor of the Lancet, he said: “There are those in the science community suggesting that we are not following the epidemiology in the right way, suggesting that perhaps we are placing too much emphasis on behavioural science.”

Downing Street has involved experts in behavioural psychology in deciding the government’s response, but the health secretary insisted the response was being guided by the best medical advice.

Hancock’s predecessor, Jeremy Hunt, said: “We now have more reported cases in this country than there were in Wuhan province [China] when they went into lockdown.”

He asked Hancock whether it was still plausible to think the virus could be contained. The health secretary replied that the World Health Organization’s decision to declare Covid-19 a pandemic had “a significant impact on the way that countries around the world will now take forward their plans”.

Jeremy Hunt, the former health secretary, pointed out his successor, Matt Hancock, that the UK now has more cases of coronavirus than when the province around Wuhan went into lockdown. Photograph: Aaron Chown/PA

The former business secretary Greg Clark pointed to the number of patients being tested for the virus declining in recent days, and asked how quickly capacity could be increased.

Hancock insisted the government was “rolling out a big expansion of testing” but declined to give a specific timetable.

Meanwhile, the Cabinet Office minister, Michael Gove, announced that Brexit talks planned for next week could be in doubt after European officials raised concerns about the spread of the virus.

The NHS has confirmed plans to increase coronavirus testing from about 1,500 suspected cases a day to 10,000.

Phillip Meyer, a businessman from Kent, said he and his son had been waiting nine days for a coronavirus test after getting a cough following a trip to northern Italy. He said: “We are testing between 1,000 and 2,000 people a day in the UK, so clearly there is a bottleneck. If in South Korea they test 15,000 a day, why can’t we do that here?”

A retired intensive care doctor told the Guardian that the increase had come “way too late” after he and his friends were repeatedly refused tests despite falling ill following a skiing trip to Ischgl, in Austria. The 55-year-old doctor from Chichester, who gave his name only as Andrew, said: “They may be upping the testing but they haven’t put Ischgl on a high-risk list, despite knowing about this for days. Six of us have been back in Chichester going about their daily life. I suspect we’ll find a big cluster in Chichester in two weeks.”

Public Health England defended its decision not to test everyone reporting symptoms. A spokeswoman said: “We are testing those who are most likely to have contracted coronavirus, either through travel or by having close contact with a confirmed case with symptoms.”