The UK government has changed advice on face-covering at school for children in year 7 or above.
In a statement published on Tuesday, Education Secretary Gavin Williamson said that children aged 12 or above, as well as adults, should wear masks at school in England's lockdown areas - which include the towns of Leicester and Luton, as well the Greater Manchester area.
Masks will be required only in the corridors and communal areas - "where social distancing is difficult to maintain" - but not in the classroom, "where protective measures already mean the risks are lower, and where they can inhibit learning."
"I hope these steps will provide parents, pupils and teachers with further reassurance", said Williamson. The measure will come into effect on September 1.
The change of advice comes in the wake of the World Health Organisation's decision to recommend masks for children aged 12 or above "under the same conditions as adults", in particular, if "they cannot guarantee at least a 1-metre distance from others and there is widespread transmission in the area."
Schools that are not in lockdown areas, however, will still have "the discretion" to make masks compulsory in the communal areas, "if they believe that is right in their particular circumstances."
Within the UK, which has Europe's highest virus-related death toll, Scottish schools reopened first, followed by those in Northern Ireland, while schools in England and Wales are due to reopen in September.
Following on from the change in WHO guidelines, the Scottish government confirmed earlier it was giving “obligatory guidance” to high school students to wear face coverings when moving around schools from Monday.