All schools in Scotland and Wales are set to close on Friday in response to the coronavirus pandemic.
This is largely down to the school systems there not having enough staff to run as normal.
There is speculation that similar measures could be announced in England.
British Prime Minister Boris Johnson has said further decisions on school closures were "to be taken imminently".
He and his government have been criticised for not moving fast enough to stop the spread of the virus.
Scottish First Minister Nicola Sturgeon has warned that people should not assume that they will open again until the end of the summer term.
She said the move was necessary because schools have now lost too many staff to continue as normal.
Ms Sturgeon said she wanted to reassure teachers and school staff that the government would work with them as they know what is best for children.
The Scottish government is still working out the finer details of what the closures will mean, she added.
Welsh education minister Kirsty Williams said schools in the country would be re-purposed to help people "involved in the immediate response to the coronavirus outbreak".
She said: "I can announce we are bringing forward the Easter break for schools in Wales. Schools across Wales will close for statutory provision of education at the latest on 20 March 2020.
"I have been clear up to now that the continuity of education and the well-being of our learners has been at the heart of my decision making. This will always be the case.
"From next week, schools will have a new purpose.
"They will help support those most in need, including people involved in the immediate response to the coronavirus outbreak."
Northern Ireland's education minister said on Wednesday that he could not give a date for when schools will be closed.
Peter Weir said that when schools close over COVID-19, it will not be short term measure, but potentially until the end of August.
The UK's Department of Education has denied several schools permission for exceptional closures.
A mother in Northern Ireland is launching legal proceedings against the decision to keep schools open there, despite the pandemic.
All schools across Ireland have been closed since Friday March 13th.