Secondary schools will have a “staggered” return in January, Downing Street has confirmed.

Exam-year students, vulnerable children and children of critical workers will go back to school as normal after the Christmas holidays, but the majority of secondary school pupils will start the term online.

It is hoped the staggered return will allow headteachers to roll out mass testing of children and staff in the new year.

Primary school pupils will go back to school as normal in January, alongside students in exam years, vulnerable pupils and key workers’ children.

In a statement released on Thursday education secretary Gavin Williamson said all pupils would be back in face-to-face education from January 11.

Williamson said: “This targeted testing round will clamp down on the virus as students return from the Christmas break and help stop the spread of Covid-19 in the wider community.

“This additional testing will catch those who have the virus but are not showing symptoms to help schools and colleges stay in control of the virus throughout the spring term.

“The new programme of daily testing for close contacts of those with confirmed cases of the virus will also mean we can keep more pupils in school, the best place for their development and wellbeing.” 

Schools and colleges will, in January, offer students two rapid tests three days apart, with positive results confirmed by a lab-based PCR test.

The DfE has said it will soon provide guidance on how to set up and staff testing sites, with armed forces personnel expected to be involved. The statement from the DfE said “reasonable workforce costs” would be reimbursed.

Those students attending face-to-face education in the first week of term will be offered the first testing dates.

With attendance plummeting as the Christmas holidays approach and cases soar in some parts of the country, schools have found themselves at the centre of a row over whether or not pupils should be allowed to learn remotely during the final days of term.

Williamson has vetoed this idea, threatening legal action against councils and schools who have said they will move to online teaching. 

A number of councils in London have now reported contact from the Department for Education (DfE) warning them of potential legal action if they go ahead with closing early amid soaring cases. However, some private schools, such as Eton, have closed early.

The Labour-run Greenwich and Islington councils were forced to row back on their advice for pupils to be taught at home in the last few days of term.

Waltham Forest Council, also under Labour control, said schools in the north-east London borough had been threatened with potential legal action by the government if they followed the council’s advice to shift learning online.

A fourth Labour-run council, Redbridge, said it would support a switch to online learning as schools faced “huge strain” due to the impact of local coronavirus cases.

The DfE said on Tuesday that lateral flow tests would be deployed to all secondary schools and colleges to “help detect asymptomatic cases and break chains of transmission”. 

It is estimated by the government that one in three people who are infected with Covid-19 do not have symptoms. 

As part of the new testing programme, students who have been in close contact with someone who has tested positive for coronavirus will also be eligible for daily testing for seven days. 

Under current rules, everyone in a school bubble must self-isolate if someone within it tests positive for Covid-19. 

But from January, those who agree to daily tests will not have to self-isolate. School staff will also be eligible for daily testing if they have been identified as a close contact.