Three-quarters of teachers and other school staff say they would be “frightened” or “worried” if their school opened to all pupils this term.
The finding from a Tes survey, so far responded to by more than 5,500 school staff, reveals the huge strength of feeling against Gavin Williamson's ambition to fully reopen schools before Easter.
Just 5 per cent of school staff say they would be "happy" if the education secretary's timetable was met.
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Teachers and other school staff were asked how they would feel working at school if all pupils returned before Easter.
"We would definitely have another spike," one secondary teacher replied. "We would be sitting ducks," said another.
"It is unsafe," a primary teacher said. "There is little hands, and no face or space."
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They were speaking after Mr Williamson said on Thursday that he “would certainly hope” that schools could fully reopen before Easter.
But that prospect has left nearly a third of school staff (31 per cent) "frightened", and another 44 per cent "worried", the Tes survey shows.
Yesterday it was reported that a government source had said that schools would not reopen to all pupils straight after half-term.
Mr Williamson is reportedly due to make an announcement on the timing of school reopenings later this week.
Asked yesterday if schools were going to return "at Easter", health secretary Matt Hancock said: "I would hope so but we have got to look at the data."
Geoff Barton, general secretary of the Association of School and College Leaders, said reports that all pupils would not be back in school until after Easter did not reflect his discussions with government.
“At a time when we are worrying about the mental health of young people, the last thing we need now is no one back in school till after Easter,” he told The Guardian.
In the Tes survey, less than a quarter (23 per cent) of teachers and other staff said they thought their school should reopen to all pupils before the start of the summer term.
Nearly one in 10 (9 per cent) thought schools should not reopen to all pupils until the start of the next academic year.
"I can't see how it's going to be safe this year," a teacher at an independent secondary said.
"Only when all staff have been immunised," said a teacher at a Knowsley secondary who also backed delaying full reopenings until September at the earliest.
"It is NOT safe, I and my colleagues are scared. We want the virus well under control. It has been a nightmare."