The Education Secretary said face-to-face teaching will continue and remain “the norm” as he outlined a series of Covid measures for schools.

Nadhim Zahawi said secondary pupils will have to wear masks in classrooms and be able to access on-site coronavirus tests at school.

A further 7,000 air purifiers are promised, to add to the 1,000 already announced, alongside 350,000 CO2 monitors.

He has also called upon former and retired teachers to return so bring additional support with a “Blitz” spirit.

Meanwhile, 12 to 15-year-olds are being encouraged to get fully vaccinated with two jabs and 16 and 17-year-old are now eligible for a booster dose.

Mr Zahawi outlined the battery of measures in a Twitter thread on Sunday, saying he wanted to offer “reassurance” before the start of term.

He said: “Teachers and support staff across the country have put in a Herculean effort over the past 18 months and more, and I know we can count on their steadfast support in the coming weeks as we weather this storm.

“I want to thank everyone from the bottom of my heart for all their efforts to help children fulfil their potential.  

“We will do everything in our power as a government to minimise the disruption to schools.”

Health Secretary Sajid Javid’s announcement last week that ministers expect a need to “constrain” supply to the general population for a fortnight amid surging demands sparked concerns over supply that have now prompted calls from the Labour Party and a headteachers’ union for the Government to make sure the tests are available for schools.

The Department for Education (DfT) is encouraging secondary, college, and university students, as well as education staff, to test themselves twice each week and have set up a priority route for schools to order kits.

Paul Whiteman, general secretary of school leaders’ union NAHT, said: “The difficulties the public have had in accessing lateral flow tests over the past few weeks has made many people nervous that they will not be available when needed for school staff and pupils.

“If lateral flow tests are to be critical to enabling pupils and staff to return to school quickly then there must be a ready supply available for schools as they go back in January and throughout the term.”

Shadow health secretary Wes Streeting was one voice urging the Government to make sure the tests are there for those who need them.

He told Sky News: “I think there are two things, though, that the Government can and should be doing.

“The first is on testing.

“Pupils should be testing twice a week.

“There’s lots of evidence to suggest that hasn’t been happening properly.

“So the message for Government is get the tests in place, make sure pupils are able to test twice a week.

“And my message to parents and pupils is ‘do take the tests’ because the big challenge this month is going to be keeping pupils learning, avoiding mass absences, and of course making sure that staff are well enough to attend school as well.”

Rev Steve Chalke, the founder of one of England’s largest academy trusts – Oasis Academy Learning told Sky News 10% of staff had been off work after testing positive for coronavirus or with other illnesses before Christmas, and staffing was still “the biggest unknown”.

However, he said DfE had done a “great job” and his schools had received all the testing kits they needed.