School leaders, teachers and parents need to be given “greater clarity” on the reopening of schools amid a rise in Covid-19 cases, a teachers’ union has said.

Boris Johnson previously pledged that all pupils at both primary and secondary schools in England will return in September, following months of closures for most students.

But after the Prime Minister announced a slowing down in easing the lockdown, Patrick Roach, general secretary of the NASUWT teaching union, said the Government will need to provide “clarification” to schools.

He told the Observer: “In light of recent changes to plans for relaxing lockdown measures, the Government needs to provide greater clarity to school leaders, teachers and parents about what this will mean for the reopening of schools in September.”

A warning from chief medical officer Professor Chris Whitty that the country is “near the limit” for opening up society will prompt questions for parents as well as teachers, Mr Roach told the newspaper.

“If schools are to reopen safely, the government will need to give them clarification about what they need to do to take account of the latest scientific evidence and advice, as well as sufficient time to review and, if necessary, adjust their reopening plans,” he added.

In response, a Department of Education spokesman directed the PA news agency to a statement saying the department had provided guidance on which control measures should be used when reopening schools.

He 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.”

Meanwhile, Dr Paul Hunter, professor of medicine at the University of East Anglia, told the Observer that although risks to children and teachers are likely to be low, this transmission would increase infection rates.

“Would reopening schools increase the spread of Covid-19 in the population? Yes. I think it would very probably do that,” he told the newspaper.

It might come down to a question of which do you trade off against each other and then that’s a matter of prioritising, do we think pubs are more important than schools?

It comes after a member of the Scientific Advisory Group for Emergencies (Sage) said ministers might have to consider closing pubs in England in order for lessons to start again next month.

Professor Graham Medley, who chairs the Sage sub-group on pandemic modelling, said this scenario was “quite possible”.

“I think we’re in a situation whereby most people think that opening schools is a priority for the health and wellbeing of children and that when we do that we are going to reconnect lots of households,” he told BBC Radio 4’s Today programme.

“And so actually, closing some of the other networks, some of the other activities may well be required to enable us to open schools.

“It might come down to a question of which do you trade off against each other and then that’s a matter of prioritising, do we think pubs are more important than schools?”