The decision to use teacher-assessed grades for A levels and GCSEs in England comes after the people in charge of the standardisation system warned such a move could “devalue” results through inflation.

The shock U-turn, announced this afternoon, was near-unthinkable just days ago, as Gavin Williamson said leaving grading up to teachers alone would mean students “lose out twice over, both in their education and their future prospects”.

Here is what has been said about the consequences of relying on teacher-assessed grades, by both the government and independent regulator Ofqual.

Ofqual: U-turn will see A-level and GCSE teacher grades stand

GCSEs 2020: Call to delay results over flawed algorithm

A levels 2020: Grades ‘utterly unfair and unfathomable’

Education secretary Gavin Williamson

Mr Williamson previously said that if A-level grades weren’t standardised, it “would devalue the results for the class of 2020”.

He added: “But worse than that, it would mean that students this year would lose out twice over, both in their education and their future prospects.”

Schools minister Nick Gibb

Mr Gibb also said using teacher-assessed grades in isolation “creates its own injustice”.

He told Times Radio last week: “If we had allowed the inflation that would have happened according to the regulator, if we had accepted just the teacher assessment with no adjustment, we’d have had inflation of 12 per cent.

“We would have had 38 per cent of all grades being A or A* compared to what it is: 27.9.

“The danger of that is you end up devaluing these 2020 A-level qualifications.”

Ofqual

The exam regulator said on A-level results day that centre-assessed grades (CAGs) were “optimistic” and, if accepted, would have led to an “unprecedented increase in overall outcomes”.

For example, the CAGs at grade A (and above) were 12.5 per cent higher than outcomes in 2019.

Using these results would “undermine the credibility of students’ grades”, Ofqual said.

The regulator said failing to standardise CAGs would also mean “any leniency or severity” in teacher grades would not be addressed - causing “unfairness between schools and colleges”.

“There was no opportunity to develop a common approach to grading across the many thousands of schools and colleges. Therefore, we developed a statistical standardisation process so that there was a level playing field for students, regardless of their school or college,” Ofqual said.

“In general, the CAGs submitted were optimistic. This is understandable and in line with the evidence from previous research.

“Our recent interviews with teachers who’ve been through the process this summer confirms that - they told us that they tended to think about how each student would perform on a good day, while knowing that every year some students have bad days. This was particularly the case for borderline students.

“The combined effect of this optimism, if CAGs had been accepted, would have been an unprecedented increase in overall outcomes.”