It is expected that grades will drop below last year but remain above those from 2019, similar to the A-level results published last week.
One education expert has predicted that, in line with the move back towards pre-pandemic grading, there could be about 230,000 less top grades in the UK compared with 2021, but 230,000 more than 2019.
Prof Alan Smithers, director of the Centre for Education and Employment Research at the University of Buckingham, said he expected top grades to fall, with more pupils failing and a slight narrowing of the girls’ lead over boys.
The Association of School and College Leaders said this week’s results were likely to be “uneven” across different schools and areas, and reflect the “turbulent circumstances” of the pandemic.
ASCL general secretary Geoff Barton appealed to schools watchdog Ofsted to bear these factors in mind and not to “rush to judgments”.
Mr Barton said that, despite schools’ best efforts to support pupils with remote education and to plug learning gaps, there would “inevitably” have been an effect on learning.
He said the government had a “lacklustre and chaotic support for education recovery”.
“It is important to understand this year’s results at school and pupil level in this context and we would urge Ofsted and regional schools commissioners in particular not to rush to judgments.”
Pupils receive their A-level results in Britain - in pictures
Ofsted said it did not base its judgments on exam results and test scores but uses data “in context, as a starting point for our discussions with school leaders about what they are teaching children and how they are running their school”.
"We have set out a range of measures to help level up education across England, including targeted support both for individual pupils who fall behind and whole areas of the country where standards are weakest," a spokeswoman for the Department for Education said.
“This is alongside £5 billion ($5.9bn) to help young people recover from the impact of the pandemic, including £1.5bn for tutoring programmes.
“Pupil Premium funding is also increasing to more than £2.6bn in 2022-23, whilst an additional £1bn is allowing us to extend the Recovery Premium for the next two academic years – funding which schools can use to offer targeted academic and emotional support to disadvantaged pupils.”
UAE pupils get their A-level results - in pictures
Last year, the proportion of GCSE entries awarded top grades surged to an all-time high after exams were cancelled for the second year in a row and pupils were given results determined by their teachers.
While traditional A*-G grades are used in Northern Ireland and Wales, in England these have been replaced with a 9-1 system, where nine is the highest.
A 4 is broadly equal to a C grade, and a 7 is broadly equal to an A.