A significant number of teachers at academy schools contacted a confidential helpline to claim they are being pressured to artificially inflate pupils' grades by school authorities, Britain's biggest whistle-blowing charity has claimed.
Public Concern at Work (PCW) has seen an 80 per cent increase in the number of complaints from the education sector during the past 12 months, boosted by a noticeable increase in calls from teachers at academy schools.
Many say they have been asked to ensure that marks for coursework and exams remain high, even if the marks are not deserved. Charity managers believe they are being contacted by academy teachers because of the removal of oversight by local authorities.
The disclosure comes as schools prepare for their A-level results, released recently. Union officials say there is concern that intense competition between schools is forcing managers to put staff under undue pressure to boost grades.
It follows previous complaints that some academies are enforcing a culture of unwarranted sackings, "unethical" sickness policies and heads who "rule through fear".
Francesca West, PCW's policy director, said there had been a noticeable increase in calls from academy staff who said they were under pressure to inflate their students' marks.
"Many concerns have come from teachers within schools with new academy status that are under pressure to maintain high results," West says.
"Where we see it being most challenging for teachers to raise concerns is in academy schools. We have identified a problem and will work on the data to see how widespread the problem is, which ages it affects and whether the pressure affects coursework and exams equally."
Academies are given more freedom over budget, time tables and curriculum than other state schools controlled by local authorities. But this has led to concerns that there is less oversight over the working environment and that teachers can be pressured into bending and breaking the rules.
The charity received 111 complaints from the education sector in the first six months of 2012; 132 in the second six months of that year; and 199 in the first six months of 2013.
A probe into claims of cheating at an academy praised by Prime Minister David Cameron uncovered three cases of exam malpractice this summer. Whistle-blowers claimed pupils at Kingsdale School in Dulwich were given too much help with their and British Technology Education Council qualifications.
Among the allegations were claims that pupils were given access to their papers to make corrections after exams, awarded grades for coursework they failed to complete and were not quarantined after arriving late for exams. Two written warnings were given to staff, though one was lifted on appeal.
Responding to the charity's findings, an education department spokesman said there was no evidence to suggest malpractice was more likely in academies than in maintained schools, and it was misleading to claim otherwise.
"More than 1,000 schools have chosen to become academies during the past year, but these claims make no attempt to take account of that," he says. "Ofqual and all the exam boards have mechanisms to deal with complaints and teachers should contact them if they have any concerns."
He said the government was taking the claims seriously and "reducing the scope for gaming by cutting back on coursework, modules and controlled assessment".