Teachers need training on how to deliver online lessons, which have been "highly variable" during lockdown, according to social mobility charity the Sutton Trust.
In a submission to the Commons Education Select Committee on the impact of Covid-19 on education and children's services, the charity said schools must have guidance on how to ensure that all pupils can access quality learning online.
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"To help and support teachers during this period of upheaval (and possible future incidences), training should be provided to enable them to deliver content to students online, and clearer guidance on expectation issued, allowing for headteacher discretion and adaptation," the charity says.
Coronavirus: Online teaching 'is highly variable'
"Online teaching being provided to children is currently highly variable, with poorer students less likely to have access to some types of provision."
The charity also says it is concerned that online provision for pupils at home could stop as some year groups return to school.
"Provision should remain in place for all pupils while they are at home, and there should be extra support provided for teachers to develop and deliver this content. It is vital that a phased return to school doesn’t risk making the situation worse for some pupils," the charity says.
The charity also called for the government's laptop scheme to be extended to all disadvantaged children, and expressed concern over delays in laptops reaching poorer pupils.
And it said summer "catch-up" provision will be needed to ensure that disadvantaged pupils can recover lost learning.