Michael Gove has thrown the full reopening of schools into doubt, with government scientists believed to have warned that some children must stay at home.
The intention for primary schools and GCSE and A-level students to return next week – and all other pupils a week later – is the plan “for the moment”, the Cabinet Office minister said.
“We do keep things under review,” Mr Gove told Times Radio. “And we’ll be talking to head teachers and teachers in the next 24 and 48 hours, just to make sure that our plans, which of course are accompanied by community testing, are right and robust.”
The scientists are believed to have concluded that the R reproduction rate would surge above 1 even if with a full, new national lockdown – if schools remained open.
However, it might be kept below 1 if schools are kept closed next month, SAGE is believed to have said, with closing secondary schools delivering a stronger benefit than shutting primary schools.
Alarm is growing because the new, more infectious strain of Covid-19 appears to have triggered greater transmission between children – with many more absent from school before Christmas.
Mr Gove added: “We have a new strain and it is also the case that we have had, albeit in very limited way, Christmas mixing, so we do have to remain vigilant.”
Any decision not to fully reopen schools would be a blow for Gavin Williamson, the education secretary, who has told allies he faces an “enormous battle” to keep secondaries open.
Officials at the Department for Education are expected to hold a crunch meeting with Downing Street on Monday, to make a decision.
Last week, Boris Johnson told a Downing Street press conference the government would stick to the plan to stagger the reopening of schools “if we possibly can”.
Mr Gove also failed to rule out the whole of England being moved into the toughest tier 4 restrictions, matching London and the south east.
“We review which tiers parts of the country should be in on the basis of scientific evidence,” he told BBC Breakfast.
“The Joint Biosecurity Centre will be making a recommendation to ministers, but I can’t pre-empt that because it obviously has to be a judgment based on the medical situation.
“As you quite rightly point out, the NHS is under pressure and these are difficult months ahead.”