Children of key workers and the most vulnerable pupils will still attend school, education secretary Gavin Williamson has said.
Boris Johnson has said he could not say how long schools would remain closed to the majority of pupils.
But Mr Williamson said the government will put in place a national voucher system for children eligible for free school meals.
He told MPs: “I know the situation has become increasingly challenging.
“I’ve said before that if the science and the advice changed, such that keeping schools open would no longer be in the best interest of children and teachers, that we would act – we are now at that stage.”
The move to close schools across England from Friday came after Wales, Scotland and Northern Ireland announced similar measures on Wednesday.
Schools supporting key workers’ children will be expected to remain open during the Easter holidays.
Nurseries and colleges across the UK are also set to close to all pupils except those of key workers in a bid to halt the spread of the virus.
Addressing a Downing Street press conference, Mr Johnson said “exams will not take place as planned in May and June” after the school closures were announced.
But he said the government would ensure that pupils due to sit exams this summer would get the qualifications they need.
The Welsh government said on Wednesday that all schools will close for an early Easter break by Friday at the latest, while Nicola Sturgeon announced schools in Scotland will also close by the end of the week.
Stormont officials said schools are to close across Northern Ireland from Monday – with the potential to remain that way until summer.
Responding to the announcement, Geoff Barton, general secretary of the Association of School and College Leaders (ASCL), said: “It is the right action at the right time.”
He added: “The cancellation of GCSE and A-level exams will inevitably cause anxiety to students and we will work closely with Ofqual on ensuring that qualifications are awarded fairly and consistently in lieu of exams.
“The priority is now to focus on maintaining provision for vulnerable children and those of key workers. We know that many schools have already drawn up plans to do exactly that and are well ahead of the curve.
“However, this is an exceptionally demanding situation and they will need support. We will be working closely with our members and the Department for Education to this end.”
The government’s decision came after a growing number of schools already decided to close fully or partially amid staff shortages.
A school in north London closed its doors to all children except those of key workers on Tuesday.
Meanwhile, a number of top private schools across the country decided to shut amid the coronavirus outbreak.
Headteachers had warned that keeping schools open has become “increasingly untenable” as staff are self-isolating.
Speaking to The Independent ahead of the announcement on closures, Mary Bousted, joint general secretary of the NEU, said school leaders were taking decisions in their own hands.
She said: “One school in Camden is closed because there are too many staff in the high-risk groups and the virus has broken out among the children. So it is not a safe environment for those teachers to be there.”
On decisions to partially close, she added: “We are hearing that some schools are keeping open for key workers’ children, but also children on free school meals and children who they feel are vulnerable.
“It has really ramped up in the last couple of days.”
Many parents had already begun withdrawing children from school this week. Dr Bousted described the school drop-off in London on Wednesday as being like a “ghost town”.
Fiona Boulton, chair of the Headmasters’ and Headmistresses’ Conference (HMC), which represents the most prestigious private schools, added that it had become “increasingly difficult” to stay open.
Ms Boulton, head of Guildford High School, said: “Heads who have had to close their schools have done so with a heavy heart because normal operations have become unsustainable and their pupils are better served by moving to online learning.
“Some will be able to keep their doors open to key workers, according to their resource.”