Education Secretary Gavin Williamson has said “we owe it to the children” to get pupils back in school, as he reassured parents it would be safe.
Mr Williamson said he knew some parents were “very anxious” about reopening schools, but said it would be a “cautious, phased return”.
It follows a row over the government’s plan to begin a phased reopening of schools in England from 1 June.
Teachers’ unions have said the date is too soon to be safe.
Speaking at the government’s daily briefing on Saturday, Mr Williamson said: “There are some who would like to delay the wider opening of schools but there is a consequence to this.
“The longer that schools are closed the more children miss out. Teachers know this. Teachers know that there are children out there that have not spoken or played with another child of their own age for two months.
“They know there are children from difficult or very unhappy homes for whom school is the happiest moment in their week and it’s also the safest place for them to be.”
England is the only UK nation to set a date for schools to start to reopen. Schools in Wales will not reopen on 1 June, while those in Scotland and Northern Ireland may not restart before the summer holidays.
Schools in England closed for most pupils on 20 March, staying open only for the children of key workers and vulnerable children.
The phased reopening will begin with children in nursery and pre-school, Reception and Years 1 and 6 at returning to primary school first an 1 June. At secondary school and college, Years 10 and 12 would return first.
But teaching unions have said plans to reopen primary schools do not have adequate safety measures and need to be halted. Some councils have said their schools will not open.
Mr Williamson said he was “always keen to listen and talk to” union leaders – who met with the government’s scientific advisers on Friday – saying: “My door is always open.”
He said the government’s approach was based on the “best scientific advice with children at the very heart of everything we do” – and the impact of it would be carefully monitored.
“We have been quite clear all along that we’d only start inviting more children when our five key tests have been met,” he said. “That position has not changed nor will it.”
Mr Williamson said school staff could already be tested for the virus and, from 1 June, children and their families would also be able to get tests if they developed symptoms.
“Together these measures will create an inherently safer system where the risk of transmission is substantially reduced for children, their teachers and also their families,” he said.
Mr Williamson said students in years 10 and 12 who were studying for their GCSEs and A-levels “stand to lose more by staying away from school”.
The education secretary also said there were no plans to bring forward the start of the next school year to August – although he was looking at “different initiatives” which could be rolled out during the summer.
Some councils – such as Liverpool and Hartlepool – have said their schools will not reopen at the start of next month.
Asked what school governors should do if the council’s stance differs from the government’s, Mr Williamson said: “What we would ask them to do is look at the guidance very, very carefully.
“The best way of protecting children, the best way of giving them the best opportunities in life is actually to have them coming back into school – and this is a very small, tentative step in what I believe is the right direction if we pass those five tests.”
The government has already issued guidance for schools, saying they should:
- Reduce class sizes and keep children in small groups without mixing with others
- Stagger break and lunch times, and school arrival and departure times
- Clean more frequently, and reduce the use of shared items and outdoor space
On Saturday, the children’s commissioner for England, Anne Longfield, said the government and unions should “stop squabbling and agree a plan” to reopen schools safely “as quickly as possible”.
She said many disadvantaged children were losing out because of schools being closed for so long.