The Government is being urged to make face-coverings compulsory in secondary schools when they finally return to class in September.
Teaching unions have called on ministers to look again at the rules so that pupils and staff have to wear masks after the summer holidays.
They claim that guidance for children over 11 to cover their faces on public transport and in shops shows they should be worn in schools and colleges too.
But the Government has ruled out making them mandatory in secondaries amid concerns they would make little difference when students and staff spend so much time together.
Some schools have already taken matters into their own hands and are making face masks mandatory or “very strongly encouraged” when pupils return to school.
Patrick Roach, general secretary of the NASUWT teachers’ union, said: “The Government’s guidance for schools is now out of step with wider public health guidance and guidance to other employers where it is recognised that where physical distancing cannot be assured, face masks should be worn.
“So there is a strong argument that face masks should also be made compulsory for children when they return to secondary schools in September.”
Julie McCulloch, director of policy at the Association of School and College Leaders, said she expected “most schools” to follow the guidance but there is “a fair degree of confusion about why face coverings are required in some settings but not in schools”.
The GMB union has written to Education Secretary Gavin Williamson urging him to adjust the “double standards” in the Government’s guidance on face masks.
National officer Karen Leonard said it was “plain common sense” that teachers and other workers in schools should be able to wear coverings.
“Changing the rules for buses and shops to enforce the wearing of masks while actively discouraging those working in schools from wearing them is causing untold confusion,” she said.
“It’s time for Gavin Williamson and his colleagues to rethink their position, provide clarity and consistency for our valuable school staff, and ensure PPE – including face masks – is available and can be worn by staff in schools where required.”
The Government has so far resisted calls to change its guidance on face coverings for school settings.
A Department for Education spokesperson said: “We have set out the controls schools should use, including cleaning and hygiene measures, to substantially reduce the risk of transmission of the virus when they open to all children from September.
“This does not include the wearing of face coverings as we believe the system of controls laid out adequately reduced the risk of transmission to both staff and students.”
Public Health England does not recommend their use as pupils and staff are “mixing in consistent groups” and using them incorrectly could increase the risk of infection.
Some European countries, including Germany, have decided to make masks compulsory for teachers and pupils.
In Spain, children aged between 11 and 18 must wear them if they can’t keep at least 1.5m apart while in France, teachers do if they’re 1m or less away from a child.