Public Health England's medical director has said that schools are not ‘drivers’ or "hubs" of Covid infection,

Dr Yvonne Doyle said she understood parents' nervousness about schools returning after the summer in England, Wales and Northern Ireland. She stressed that lots of measures to cut Covid spread remained in place.

But Prof Calum Semple, a government scientific adviser, said with most adults vaccinated, schools were likely to be a greater part of the problem. Some have suggested a surge in cases in Scotland, where pupils returned in August, could be linked to schools.

Fewer measures are in place in schools than during last term, with bubbles and masks no longer in use in England and Wales, while Northern Ireland has also scrapped social distancing requirements. Education Secretary Gavin Williamson said it was right for children to have a much more normal education experience, with adults being able to go back to the pub, music festivals and theatres.

He said there needed to be a sensible balance and that was why mass testing of secondary school pupils was taking place. Dr Doyle said there were lots of regimes in place already to prevent the spread, including extra cleaning, advice on ventilation and testing.

She said: "We understand, and I understand fully, that parents may be nervous but I would stress again that schools are not the drivers and not the hubs of infection." She added that PHE attributed some of the school-related coronavirus figures to the testing regime.

Professor of child health and outbreak medicine at the University of Liverpool, Prof. Semple, said he believed schools should stay open nearly at all costs because the damage caused by a lack of education could be lifelong. He said while pupils were unlikely to get sick themselves they could transmit the disease to others, and that this should be considered when discussing vaccines for 12 to 15-year-olds.

A paper, published by the Royal Society, suggests the reopening of schools, and particularly secondary schools, is associated with an increased risk of transmission both among school-aged pupils and in the wider community. But it said the scale of that increase depended on control measures in the classroom and community as well as compliance with mass testing.

Prof Semple said his biggest worry was closing schools again because education was very important but he said school building stock was poor, with ventilation an issue.