Schools in Scotland and Wales are to close from Friday in response to the coronavirus epidemic.
It is expected the UK government will announce shortly that schools in England will follow suit.
Scotland First Minister Nicola Sturgeon says schools have now lost too many staff to continue as normal.
The coronavirus death toll in the UK has now reached 104 after the NHS said a further 32 people had died in England after testing positive.
Confirmed coronavirus cases in the UK rose to 2,626 on Wednesday, from 1,950 on Tuesday. There have been 56,221 tests carried out in the UK for Covid-19, of which 53,595 were confirmed negative.
The government says it plans to more than double the number of tests being carried out in England to 25,000 a day.
It comes as frontline doctors expressed concerns about the lack of testing among NHS staff and the shortage of protective equipment.
Meanwhile, the government is bringing forward emergency legislation to protect private renters from eviction after being urged to do more for them.
On Tuesday, Chancellor Rishi Sunak announced £350bn of help for companies and mortgage “holidays” for home owners.
In other developments:
- UK supermarkets bring in strict limits on purchases
- European Union countries have begun turning away travellers from outside the bloc
- Share prices fell in Europe and Asia as stimulus packages failed to reassure markets
- The World Health Organization said South East Asian countries must “act now” to tackle the virus
- There are more than 200,000 cases worldwide and more than 8,000 people have died
- Princess Beatrice says she is reviewing plans for her wedding to Mapelli Mozzi at St James Palace on 29 May and has already decided to cancel a reception in Buckingham Palace gardens
- Britons in Spain are being urged by the Foreign Office to return to the UK before 24 March when all Spanish hotels close
- The BBC puts filming of EastEnders on hold and Glastonbury Festival is postponed
- The Eurovision Song Contest, due to be held in the Netherlands, was cancelled
- Prof Neil Ferguson, who has been advising the UK government on its response to the outbreak and was in Downing Street earlier this week, tweeted he was self-isolating after developing coronavirus symptoms
- An inmate at HMP Manchester becomes the first prisoner to test positive for coronavirus and is currently in hospital. The Ministry of Justice says 13 prisoners and four staff members are in isolation as a precaution
The move on schools in Scotland and Wales will be welcomed by headteachers who have been struggling to keep their doors open, with growing numbers of staff and pupils off school.
Schools have been pressing for a decision on keeping them open over the past week, as growing numbers of staff have called in sick and parents stopped sending their children into class.
Schools have been preparing for a shut down for some time, with some creating homework packs or setting up ways of working online.
But there have been concerns about the ability of frontline NHS staff and others to remain in work if their children are not in school.
Headteachers’ leaders have been meeting regularly with the education secretary over the last few days.
They have been seeking to balance between keeping their staff and pupils safe in the face of the virus outbreak, and the need for vulnerable pupils to be supported.
The prime minister’s official spokesman stated that the possibility of school closures had always been part of the plan “should the medical and scientific advice state that was the right step to take and that we have reached the right moment to do so”.
Prime Minister’s Questions took place in a half-empty House of Commons, after Labour and the Conservatives told MPs not scheduled to raise a query to stay away.
Paying tribute to teachers’ efforts, Mr Johnson told MPs he wanted to do more to “remove burdens on schools” and said further decisions would be taken imminently on schools and how to “square the circle – making sure we stop spread of the disease but relieve pressure on the NHS”.
Education Secretary Gavin Williamson is expected to make a statement on the situation in England at 17:00 GMT.
Wales education minister Kirsty Williams said she was bringing forward the Easter break and all schools would close by Friday at the latest.
Childcare centres are expected to remain open until further advice is given, Ms Williams added.
Ms Sturgeon said schools and nurseries across Scotland would close from the end of this week and may not reopen before the summer.
Northern Ireland’s education minister Peter Weir said he could not give a date for school closures but any shutdown could potentially last until the start of the autumn term.
On help for renters, Kate Henderson, of the National Housing Federation, confirmed housing associations would not evict tenants who were affected by the virus and fell behind with their rent.
Labour leader Jeremy Corbyn urged the prime minister to protect renters in “the interests of public health”, saying Britain’s 20m private renters were “worried sick” about missing payments if they became ill, lost pay or had to self-isolate.
Among the latest confirmed cases in the UK is a newborn baby at James Paget hospital in Norfolk.
And a man in his 40s with motor neurone disease is thought to be the youngest person in the UK to have died having tested positive for coronavirus. Craig Ruston died in Kettering, Northamptonshire, on Monday morning.
In other UK developments:
- Parkrun, which organises 5km weekly runs around the world, has suspended its 675 events in the UK until at least the end of March
- Department store chain Selfridges is closing its London, Birmingham and Manchester stores from 19:00 GMT on Wednesday
- The United Synagogue – the biggest group of synagogues in the UK – has closed all of its synagogues until further notice
- Honda is to suspend production at its Swindon plant until at least 6 April – joining Nissan, Toyota, BMW and Vauxhall which are also ceasing operations for the time being
- All non-urgent operations in England and Scotland will be postponed from 15 April for at least three months to free up beds
- No new Crown Court trials will take place in England and Wales if they are expected to last longer than three days