Sir Iain, a former Tory leader, told The Telegraph the data showed that “we’ve got to hold our nerve”, adding: “I think this move [face masks in schools] is premature. I think we’ll see Covid spike and start to fall like it did in South Africa.

“It’s far better to test pupils than to mandate masks. They will be worn badly and won’t stop contact between kids. I don’t know who they’re going to protect – the teachers should be triple jabbed by now. It’s very important that the schooling isn’t wrecked as a result of this.”

Mr Jones said that he was “worried” about the measures because they could have a “counter-productive effect on education”. In light of the latest data, he said the Government “should be very, very reluctant to impose that restriction on children who are suffering enough challenges”, urging ministers to think again.

Andrew Bridgen, the Tory MP, said he was also strongly opposed to the decision to mandate masks for secondary school pupils, adding: “I think the children have suffered immeasurably during this pandemic and these measures are taken to try and protect others. I honestly feel that the legacy of Covid is going to be the damage we’ve done to our children.”

His concerns were echoed by Robert Halfon, the chairman of the education select committee, who called on the Government to balance the risk of Covid against the long-term impact on children’s mental health and well-being.

Prof Viner, professor of adolescent dealth at UCL and a member of Sage, said he only supported the move to introduce face masks with “a very heavy heart”. He added: “There are clear downsides to wearing masks, but the biggest downside of all would be children not being in school.”

The former president of the Royal College of Paediatrics and Child Health said there was “very little direct evidence that mask wearing in schools reduces transmission” but that transmission among teenagers is “similar to that of adults”, where there is proof face coverings are effective.

He added that “there is lots of evidence of harms around mental health, increased anxiety and issues with socialisation” and that masks can exacerbate this in adolescents and “isolate people”.

Dame Rachel said that if the use of masks was a short-term measure it was “the lesser of two evils” because “the harm of children not being in school, to me, is far greater”. But she added: “I worry that it is just another case where we’re expecting children to take the hit rather than anyone else in society, and it just seems a bit unfair.”