Schools are getting prepared to switch to online learning if they have to next term, as more children stay at home due to coronavirus.
Some children are being asked to take laptops home with them before Christmas in preparation.
More than 30 local authorities told the BBC that schools had already been forced to move some classes online.
The Government however has insisted that it is committed to ensuring that schools in England stay open in January.
Schools across the UK are being told to reopen next term under current guidance.
They have been planning for a number of scenarios - including remote learning and teaching in “bubbles” with staggered start and finish times.
Official figures show 236,000 students were out of school for Covid-related reasons in England on December 9, marking a 13 per cent increase compared two weeks earlier.
In east London, children at two primary schools managed by the Letta Trust will be sent home with their laptops when they break up for Christmas, in case they cannot come back for the start of next term.
Meanwhile, vulnerable children are also being provided with laptops before Christmas in Kingston-upon-Thames.
Only a handful of schools have been forced to close early before Christmas because of Covid.
Those that have include one in York, one in Hillingdon and two in Leicestershire, while some in five parts of Wales have opted to move to online learning.
It comes as Education Secretary Nadhim Zahawi called on on school leaders to encourage ex-teachers “to sign up” to help with Covid staff shortages.
In an email to heads, the minister said the Government was looking at what measures to put in place “to boost supply capacity”, adding that Department for Education officials have begun to discuss plans with key stakeholders.
“We know that in areas with high absence a particular issue can be the availability of supply staff. We want to make sure that as many supply staff as possible are available to schools and colleges,” Mr Zahawi said.
The Education Secretary added: “We will work with sector leaders and supply agencies over the coming days to offer advice to ex-teachers who want to provide support to schools and colleges.
“We will help them to register with supply agencies as the best way to boost the temporary workforce available to the sector.
“From now, you can support this effort by using your own professional and personal networks to encourage others to sign up to offer temporary help.”