Students and staff in some parts of England are being asked to wear face coverings again after a rise in coronavirus cases.
Mask-wearing stopped being compulsory in May, but the government is reserving the right to re- introduce it under its winter plan.
What are the rules about masks in schools?
Face coverings are no longer compulsory in schools in England or Wales, although they are recommended in crowded spaces like school buses.
However head teachers and health officials can ask staff and pupils to wear masks on school premises in response to local circumstances.
Schools in Bedfordshire, Trafford, Cambridgeshire and West Yorkshire have already reintroduced face coverings.
Education Secretary Nadhim Zahawi confirmed that mask-wearing in all English schools could be made compulsory again under the government’s winter contingency “Plan B”.
In Scotland, face coverings are required at least until October half-term.
In Northern Ireland, they are required in class for at least the first six weeks of term.