"Good schools" will ask teachers to work over half-terms, weekends and in the evenings to help disadvantaged pupils catch up, a former head of Ofsted has said.
Sir Michael Wilshaw said summer school programmes will not be enough to help those pupils who have fallen behind due to the coronavirus outbreak.
Coronavirus: ‘Open schools over summer holidays’
Speaking on the BBC's Newsnight programme last night, the former chief inspector was asked whether disadvantaged pupils would be able to catch up after spending long periods out of the classroom.
Coronavirus: Disadvantaged pupils 'will need more than summer school'
He replied: "I doubt it. They’ve lost 12 weeks, they’ll lose even more…it’ll need more than a summer school programme to make up the lost ground.
"I would imagine good schools will be saying to their staff, ‘We want you to come in over weekends, we want you to do twilight programmes, we want you to come in over half-term breaks as well.
"Now the unions might cavil against that but I think a lot of teachers who will want to do well by their children will do that voluntarily, and the government – if there is money – should be incentivising school budgets to help headteachers pay them in those times."
WATCH: Sir Michael Wilshaw on why teachers need to work through their holidays:
He was speaking during a week when details of a "huge summer of catch-up" are due to be announced by the government.
But Sir Michael said he worried that if summer school programmes are held in venues other than schools, pupils may not show up.
"The children will want to go back into the school they know, where they’ve formed a relationship with the teachers," he said.
Sir Michael also said footballer Marcus Rashford was right to call on the government to provide free school meals over the summer.
"Lots of headteachers", he said, are so worried about "the poorest children who have lost out the most during this crisis" that they are "bringing children in over the summer break [and] inviting their staff into school over the summer break to teach them to make sure they don’t lose out even more, at their own expense".
He added: "If they’re going to be doing that and children are going to be coming into school over the summer break to catch up, they need food and they need sustenance and I think that the government should listen to Marcus Rashford and headteachers."