An investigation has been launched into reports that some of the laptops handed out to vulnerable children for homeschooling are infected with a virus.
Teachers from schools in Bradford, Lincolnshire and Wolverhampton said on an online forum they noticed the issue and believe it contacts Russian servers.
One person wrote: 'Upon unboxing and preparing them it was discovered that a number of the laptops are infected with a self-propagating network worm (Gamarue.I).'
Gamarue.I, identified by Microsoft in 2012, is a worm capable of downloading files on to a PC.
According to the tech firm, it can be installed when a spam email attachment is opened and can also copy itself to any USB flash drives connected to the computer.
The Department for Education (DfE) said it is looking into the problem as a matter of urgency but does not think it is widespread.
Teachers from schools in Bradford, Lincolnshire and Wolverhampton said on an online forum they noticed the issue and believe it contacts Russian servers (file photo)
Bradford Council alerted schools in the area of the issue on Wednesday, saying 'the network worm looks like it contacts Russian servers when active'.
A council worker said institutions should treat it as a 'matter of urgency' and told them to check to see if their networks had been hacked.
A school IT employee from Wolverhampton wrote online: 'I know bad news isn't what we need right now but we've just fired up a bunch of these to prep [them] and a number of them have alerted... that a worm has been found.'
Another from Lincolnshire posted they had found problems on their computer systems as well.
The laptops were delivered by IT reseller XMA, according to the Telegraph, which is one of three firms helping the government dish out the equipment.
The company was paid £12million to distribute 69,000 devices, with an option for an extra 60,000 boosting the contract to £22million.
Another £5.7million contract shows the XMA agreed last year to deliver 26,449 more by November 13.
The Government has committed to giving 1.3million laptops and tablets to poorer children during lockdown, with more than 800,000 of these delivered already.
The Government has committed to giving 1.3million laptops and tablets to poorer children during lockdown, with more than 800,000 of these delivered already. Pictured: Education Secretary Gavin Williamson
A DfE spokesman said: 'We are aware of an issue with a small number of devices. And we are investigating as an urgent priority to resolve the matter as soon as possible.
'DfE IT teams are in touch with those who have reported this issue. We believe this is not widespread.'
Brian Higgins, security specialist at Comparitech, said: 'Whilst it is unclear where these particular laptops were sourced, it is absolutely vital that anyone seeking to source devices, whether they are bought using sponsorship or donated directly, be fully aware of the risk that they may contain dormant or active malicious software and research appropriate methods to make them safe before they are distributed to homes and families.
'The potential for malicious software to be used against recipients is not limited to the children for which the devices are intended, as access to the internet will no doubt be useful for other family and friends outside of school hours.
'I would highly recommend that anyone distributing devices include some information about online safety.'
It comes as a damning report revealed more than a third of low-income households do not have the laptops and tablets needed for remote schooling.
More than a third of low-income households do not have the laptops and tablets needed for remote schooling, a damning report reveals today
Pupils have been told to use the devices to learn at home while schools are closed to most children.
This has opened a 'digital divide' between middle-class children and pupils from low-income households who are struggling without computer access.
The extent of the divide is laid bare in a survey by the Sutton Trust, a social mobility charity, which found that 35 per cent of families are still lacking sufficient access to devices, compared with 11 per cent of high-income homes.
Problems have been compounded by the Government's sluggish progress in delivering laptops and tablets, with only 800,000 out of a promised 1.3million distributed so far.
School Covid test plans is put on hold
Ministers have suspended plans for mass daily testing of pupils and teachers amid growing fears the closure of schools could last until April.
Last month, Education Secretary Gavin Williamson said rapid testing for Covid-19 would be a 'milestone moment' in allowing schools to stay open.
The plans were intended to keep more children in school by sending home only those who tested positive after a rapid lateral flow test.
In theory, this would eliminate the need for entire class 'bubbles' to be sent home.
But health experts questioned the safety of the system, and yesterday the Department for Education admitted the plans were on hold other than for a small number of schools who were evaluating them.
Ofcom has estimated up to 1.78million children have no access to a computer.
Their work did not take into account the many more sharing devices with siblings and parents.
Worse still, the survey revealed state school teachers are saying more than one in five of their pupils completely lack computer access.
This could be because parents who are out of work as a result of the pandemic are having to return computers to employers, use them to look for work, or they may be struggling to afford internet bills.
Three quarters of secondary school heads said they have been forced to try to source laptops while they wait for government supplies.
Despite their efforts, only 10 per cent of teachers reported that all their students have adequate access to a device for remote learning.
And only five per cent of state school teachers said all of their students have internet access.
The effect on children's education is already starkly apparent.
According to the survey, 40 per cent of children in middle class homes are learning for more than five hours a day, compared with 26 per cent in working-class households.
Sir Peter Lampl, founder and chairman of the Sutton Trust, said that the impact of lost learning was 'devastating and will be felt for years to come'
'The immediate priority has to be to address the gap in digital provision between rich and poor,' he added.
The Trust is recommending that laptop and internet access 'should continue to be rolled out at speed through the government programme'.
'Every day that goes by with pupils lacking access to the tools for online learning widens gaps and harms the long-term prospects of young people,' the report added.
The charity is also calling for a one-off £750million pupil premium boost that would give schools an additional £400 per eligible pupil to spend to help them catch up.
Ofcom has estimated up to 1.78million children have no access to a computer
Most school staff in the survey cited a faster rollout of laptops as the single most helpful intervention for poorer pupils.
The findings are based on polls of 6,475 teachers and 877 parents taken this month.
A Department for Education spokesman said: 'We are aware of the additional challenges faced by disadvantaged children during this crisis, which is why we are providing 1.3million laptops and tablets, alongside access to free mobile data.'
XMA has been contacted for comment.