Boris Johnson said he has "no doubt" that schools are safe and parents should send primary-age children back to classrooms this week where schools remain open.

Mr Johnson said he understood people's concerns about children returning for the new term but said education is "a priority".

Speaking on The Andrew Marr Show on BBC One, the prime minister said: "Schools are safe. It is very, very important to stress that.

"The risk to kids, to young people is really very, very small indeed.

"The risk to staff is very small.

"I would advise all parents thinking about want to do, look at where your area is, overwhelmingly you'll be in a part of the country where primary schools tomorrow will be open."

He added: "I understand people's frustrations, I understand people's anxieties but there is no doubt in my mind that schools are safe and that education is a priority."

Gavin Williamson confirmed on Friday that all London primary schools will remain shut to most pupils next week - rather than just those in certain boroughs as set out earlier in the week - but teaching unions say all schools should close for the next two weeks.

On Saturday evening, the Department for Education said remote learning was "a last resort" and classrooms should reopen "wherever possible" with appropriate safety measures to help mitigate the risk of transmission.

"As we've said, we will move to remote education as a last resort, with involvement of public health officials, in areas where infection and pressures on the NHS are highest," the spokesperson said.

Hundreds of new vaccination sites are due to be up and running this week as the NHS ramps up its immunisation programme with the newly approved Oxford University and AstraZeneca jab.

Some 530,000 doses of the vaccine will be available for rollout across the UK from Monday and more than a million patients have already had their first dose of the Pfizer/BioNTech vaccine which was the first to be approved by the Medicines and Healthcare products Regulatory Agency.

But Ofsted chief inspector Amanda Spielman, writing in the Sunday Telegraph, said: "It is clear that children's lives cannot just be put on hold while we wait for vaccination programmes to take effect, and for waves of infection to subside.

"We cannot furlough young people's learning or their wider development. The longer the pandemic continues, the more true this is."

Children's Commissioner Anne Longfield told the newspaper that schools should be the last to close and first to open, when safe to do so, adding: "I hope, for children and parents' sake, that is measured in days not weeks and I would be particularly keen for primaries to stay open if at all possible."

Labour leader Sir Keir Starmer said the vaccine roll-out was "our great hope", adding: "I want the Government to throw everything it can at this, harnessing the extraordinary talents of our NHS so we can be vaccinating at least two million Brits a week by the end of the month."

But, writing in the Sunday Mirror, he criticised "a chaotic last minute U-turn on schools", adding: "Confusion reigns among parents, teachers and pupils over who will be back in school tomorrow and who won't."

Norfolk MPs and councillors were split on the issue of returning to schools.