More than 2,000 head teachers have called for summer exams to be scrapped this year as plans to reopen schools were plunged into fresh chaos.
Secondary school pupils face a staggered start to their term, while all primary schools in London staying shut next week.
Most primary schools in England are scheduled to reopen on Monday but the Government is under mounting pressure to keep children at home amid spiralling coronavirus infection rates.
Under-fire Education Secretary Gavin Williamson has insisted that GCSE and A-Levels must still go ahead, despite end-of-year exams being ditched in Scotland and Wales.
But more than 2,000 head teachers, from the campaign group Worthless?, say pupils, parents and teachers should not be put at risk of contracting Covid for the sake of protecting exam timetables.
And former chief schools inspector Sir Michael Wilshaw said A-levels and GCSEs should already have been axed as thousands of exam-year pupils had missed classes.
The calls come amid fears over the spread of the new coronavirus strain, as confirmed cases were higher than 50,000 for the fifth day in a row when UK figures were released on Saturday.
A record-high of 57,725 lab-confirmed cases were recorded and another 445 deaths within 28 days of a positive test.
“Wider public health, pupil and staff safety should be prioritised ahead of examinations,” head teachers from WorthLess? told The Sunday Times.
“Public safety should not be risked or driven by an inflexible pursuit of GCSE and A-levels.”
One of the group’s leaders, Jules White, head of Tanbridge House School in Horsham, West Sussex, said there was “great scepticism that exams can now go ahead fairly”.
Recommending teacher assessments for final grades instead, the group said it would be unfair on pupils in areas hit harder by the pandemic than others to go ahead with exams.
Sir Michael, who served as Ofsted boss from 2012 to 2016, told the Sunday Mirror: “Exams this summer should have been cancelled but I think it’s too late now.
“They’ve pinned their colours to the mast very firmly on this one. It would be an embarrassing U-turn.
“If I was a head teacher in a high-infection area with staff and children regularly off, I would be saying to the Government ‘how on Earth can these children be well prepared for an exam in five months?’ The other home nations have cancelled exams, but this Government is not going to do that.
“For Williamson to make another U-turn on top of the other U-turns he has made would be very embarrassing for him, the Department of Education and the Government.”
Mr Wilshaw added there was no sign of a “plan B” if Covid means that exams eventually do have to be axed as happened last year.
He said: “What they should be doing is putting in really robust contingency arrangements. But they haven’t done that.”
“Sadly, this is a department of short-termism and last minutery.”
Former education secretary Lord Baker said teachers should be allowed to do assessment grade of pupils’ performances rather than having them sit exams.
“They (teachers) are better than algorithms and they are the only people who can possibly assess the achievement of their students in this extraordinary time,” he said.
Writing in the Sunday Mirror, he said: “Confusion reigns among parents, teachers and pupils over who will be back in school tomorrow and who won’t.”
Mary Bousted, General Secretary of the National Education Union (NEU), called for a two-week closure to “break the chain” of transmission and prevent the NHS becoming overwhelmed.”
The union, which represents the majority of teachers, has advised its members it is not safe to return to classrooms on Monday.
NAHT general secretary Paul Whiteman said the union had started preliminary steps in legal proceedings against the Department for Education, asking it to share its scientific data about safety and transmission rates.