Schools in the UK are to shut from Friday until further notice as a response to the coronavirus pandemic, the Prime Minister has said.
Schools will close except for looking after the children of keyworkers and vulnerable children.
Exams will not go ahead, education secretary Gavin Williamson has said.
Scotland and Wales earlier said schools would close from the same day while schools in Northern Ireland will close to pupils today and staff on Monday.
It comes as UK deaths reached 104 after the NHS said a further 32 people had died in England.
The government says it plans to more than double the number of tests being carried out in England to 25,000 a day.
Confirmed 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.
Boris Johnson said: “We think now that we must apply further downward pressure with that upward curve by closing the schools.
“After schools shut their gates to most pupils, they will remain closed to the majority of pupils.”
He thanked teachers and head teachers and said that by looking after children of key workers, such as NHS staff, they “will be a critical part of the fight back” against coronavirus.
Announcing the shutdown of schools in England, following similar announcements in Scotland, Wales and Northern Ireland, Education Secretary Gavin Williamson told MPs assessments or exams would not go ahead this year and performance tables would not be published.