A teaching union is calling for a delay to the reopening of schools in January as the Government hopes to push ahead with its new year plan.

Earlier this month, the Government said exam-year students would go back to school as normal after the Christmas holidays, but the majority of secondary school pupils would start the term online to allow headteachers to roll out mass testing of children and staff.

Officials from Downing Street and the Department for Education were due to discuss the issue on Monday amid concerns over the spread of a new strain of coronavirus, although the DfE said it was not commenting on the outcome of the meeting.

Dr Patrick Roach, general secretary of the NASUWT, wrote to the Education Secretary on Monday demanding further action on school safety.

The letter calls for Gavin Williamson to allow schools to move to remote learning for all pupils, except those deemed to be vulnerable or the children of key workers, in the highest tier areas.

“Delaying the return of pupils to schools and colleges at the start of the spring term will also enable all school and college employers to undertake and consult as required on new risk assessments and ensure that they can be compliant with any new measures or requirements contained in any forthcoming national guidance,” it says.

The union is also asking the Government to publish new safety guidance in light of the new Covid-19 variant, introduce mandatory face coverings within schools and give staff priority access to the vaccine.

Mary Bousted and Kevin Courtney, the joint general secretaries of the National Education Union (NEU) have also written to Mr Williamson, along with Prime Minister Boris Johnson, reiterating calls for schools and colleges to remain closed for at least the first two weeks of January, except for vulnerable children and the children of key workers.

The letter asks the Government to share the evidence and advice received from experts about schools reopening from the chief medical officer.

“You certainly cannot expect education staff to show good will towards your plans for education if you do not at least share all the information you have about this dreadful disease with them,” it states.

It came as Cabinet Office minister Michael Gove said the Government hopes the staggered reopening of schools in England will go ahead in the new year as planned.

Speaking to the BBC Radio 4 Today programme, Mr Gove said ministers were confident primary school pupils and Year 11 and Year 13 pupils in England would be able to return in the first week of January, with the rest going back later in the month.

“It is our intention to make sure we can get children back to school as early as possible,” he said.

“We are talking to teachers and headteachers in order to make sure we can deliver effectively. But we all know that there are trade-offs.

“As a country we have decided – and I think this is the right thing to do – that we prioritise children returning to school.

“But we have a new strain and it is also the case that we have also had, albeit in a very limited way, Christmas mixing, so we do have to remain vigilant.

“We are confident that we will be able to get schools back in good order. Our plan and our timetable is there, and we are working with teachers to deliver it.”

He told Sky News: “We always keep things under review but teachers and headteachers have been working incredibly hard over the Christmas period since schools broke up in order to prepare for a new testing regime – community testing – in order to make sure that children and all of us are safer.”

Scientists have suggested that the mutated coronavirus strain could more easily infect children.

Sir Jeremy Farrar, a member of the Government’s Scientific Advisory Group for Emergencies (Sage), said the arguments for reopening schools in January were “very finely balanced”.

“I think the next few weeks going into January are going to be extremely difficult across the whole country,” Sir Jeremy, director of the Wellcome Trust, told Today.

You cannot have the whole of society opening, and schools opening and further education and universities, and keep R below 1 with this variant

“Certainly my own view is that schools opening is an absolute priority. But society – and eventually this is a political decision – will have to balance keeping schools open, if that is possible, with therefore closing down other parts of society.

“It is going be a trade-off between one or other. You cannot have everything. You cannot have the whole of society opening, and schools opening and further education and universities, and keep R below 1 with this variant.”

Labour’s shadow education secretary Kate Green said: “Labour has been clear that keeping pupils learning should be a national priority, but a litany of Government failures, from a lack of funding for safety measures through to the delayed and chaotic announcement of mass testing, is putting young people’s education at risk.

“It is time for the Prime Minister to get a grip on the situation and show some leadership.

“The country needs to hear from him today, alongside the chief medical officer and chief scientific adviser, about the evidence on the spread of the virus, how he plans to minimise disruption to education and a clear strategy for schools and colleges that commands the support of parents, pupils and staff.”

A Government spokeswoman said: “We want all pupils to return in January as school is the best place for their development and mental health, but as the Prime Minister has said, it is right that we follow the path of the pandemic and keep our approach under constant review.

“Our huge expansion of rapid testing will support secondary schools and colleges to stay open to all pupils and reduce the risk of transmission within local communities.”