Closing schools is the last possible option in the fight against the new Omicron variant of coronavirus, the Education Secretary has said.

Nadhim Zahawi said he does not support the return of “bubbles” in schools – where whole classes or year groups could be sent home after a positive Covid-19 test – as it reduces attendance “significantly”.

His comments came as targeted testing of pupils began in two schools in Essex and Nottinghamshire after cases of the Omicron variant were detected in the local areas.

Face masks are being recommended in communal areas of England’s secondary schools and colleges, but teaching unions are calling for tougher measures to be implemented to stop the spread of coronavirus.

The Education Secretary told ITV’s This Morning programme: “The best place for children to be is in a classroom, learning.”

Asked if closing schools was the “last possible option”, he said: “Absolutely.”

Mr Zahawi added: “Keep schools open: do all the things necessary, like face masks in communal areas… to protect the education in the classroom.

“Face masks are not a panacea… these are all interventions that just help you slow the virus… from accelerating too quickly.”

The Education Secretary said he disagreed with the idea of a return of bubbles in schools as “that reduces attendance significantly”.

Senior Tory MP Robert Halfon, chairman of the Education Committee, called for confirmation that schools would not be closed early for Christmas.

Health Secretary Sajid Javid said: “There are no plans that I am aware of that would require us to close schools early, I think that would be very detrimental to the education of children.”

The National Education Union (NEU) has suggested face coverings could also be worn in secondary school classrooms, and schools in England could consider “bubbles” to reduce the spread of coronavirus.

Dr Mary Bousted, joint general secretary of the NEU, said: “The best place for children is at school and the last thing we want is to see more disruption to education.”

But she added: “Covid does not recognise the difference between a corridor and a classroom, and a failure to require face coverings in both areas in secondary schools is a mis-step in the latest guidance.

“We also believe that arrangements for close contacts should mirror that of Scotland. Schools may wish to consider bubbles to help stop the spread, and in relation to local case rates and any outbreaks within the school.

“Masks in communal areas are there to stop the spread between classes, and bubbles with different playtimes and lunch sittings would help with the same aim. This will be a challenge for schools with limited space but is in the interests of keeping education going.”

Pupils at Larchwood Primary School in Essex are being tested for the Omicron variant of Covid-19 – and one class has switched to remote learning – after a link was found with a case in Brentwood.

Meanwhile, targeted testing at a school in Nottinghamshire also took place on Monday as a “precautionary measure” after an Omicron variant case was detected locally, Nottinghamshire County Council said.

Julie McCulloch, director of policy at the Association of School and College Leaders (ASCL), added: “Many schools are already experiencing high levels of Covid-related pupil and staff absence and this may necessitate switching year groups to remote education for short periods of time.”

Paul Whiteman, general secretary of school leaders’ union NAHT, said: “Given the level of uncertainty and worry about the new variant, it would seem sensible for the government to take a precautionary approach.

“They cannot risk moving too slowly and not doing enough, as happened at the end of the winter term in 2020.

“We would urge them to take every safety measure possible while maintaining face-to-face education, in order to avoid longer-term school closures.”

Justine Roberts, founder and chief executive of Mumsnet, said: “There’s widespread concern on Mumsnet from parents and teachers alike about how schools will fare in light of this new variant.

“Many fear a repeat of the U-turns and closures seen over the past year, and there’s sadness and frustration as nativity plays and Christmas activities are being cancelled.”

She added: “The overwhelming call from our users is for urgent support and guidance from the Government to mitigate the spread and keep schools open – whether that’s mask mandates, investment in ventilation and CO2 monitors, or the return of classroom ‘bubbles’.”

The Prime Minister’s spokesman said on Monday that the Government was not looking to close schools early for Christmas.