Schools across the UK will close from Friday until further notice, the education secretary has announced.
Speaking in the House of Commons, Gavin Williamson also confirmed that exams and assessments would not be held this academic year.
He told MPs: “I want to provide parents, students and staff with the certainty they need.
“After schools shut their gates on Friday afternoon, they will remain closed until further notice.
“This will be for all children, except for those of key workers and children who are most vulnerable.
“The scientific advice shows that the settings are safe for this small number of children attending, but asking others to stay will just go towards helping us slow the spread of this virus.”
Mr Williamson said examples of key workers include NHS staff, police and delivery drivers.
Mr Johnson’s government had resisted calls to close schools, because NHS workers would be among those who may need to stay home and look after their children.
But teachers, head teachers and unions have warned that many schools are so short-staffed that they are struggling to remain open.
The NASUWT, which represents teachers and headteachers, has warned of a “rising sense” of panic in the education sector over COVID-19 and said on Tuesday a lack of advice was creating “chaos and confusion”.
Chris Edwards, headteacher of Brighton Hill Community School in Basingstoke, told Sky News earlier: “I feel like occasionally I am putting staff in harm’s way asking them to teach in crowded classrooms.
“Equally for the students, they’ve got to be our number one priority – at the end of the day we are here for the students and we always will be and if we are told that it stays open, we will continue to stay open, if we feel that’s what’s best for the welfare of the children.
“This is where many of them feel safest, and that’s a big responsibility.”