A huge number of pupils are refusing to wear masks in school or take lateral flow tests, according to reports.
A union says older pupils are refusing to stick to the rules designed to stop the rapid spread of Omicron variant Covid in younger people.
Since the start of this year the Government has asked pupils across England to wear masks in classrooms as well as corridors and other communal areas.
Damien McNulty, from the NASUWT teachers' union, told the BBC there are "huge numbers" of pupils refusing to wear masks and take lateral flow tests.
He spoke about six secondary schools in the north-west of England - which is the current hotspot for the spread of Covid in the UK.
He said at one time just 67 pupils in one school of 1,300 were willing to wear masks or take tests. And he said the pattern is likely to be the same across the country.
He said the situation is being made worse as supply teachers are 'in charge' thanks to high staff absence caused by Covid.
Year Eight pupil Molly told the BBC: "A teacher will say 'can you please put your masks on?' And they'll just say 'no, we don't need to wear masks, we don't want to wear them'."
Steve said his 16-year-old daughter told him 'quite a few' pupils at her school are not wearing masks.
He said: "I'm slightly surprised that they haven't got the ability to enforce the situation."
A DfE spokeswoman told the BBC: "Schools know their pupils best and can decide how best to encourage them to wear face coverings and take Covid tests.
"No-one should ever be denied education on the grounds that they are, or are not, wearing a face covering."
