A charity has raised concerns that the coronavirus crisis has widened the gap between independent and state schools after it was revealed that just over 70% of all A-level entries from private schools in England were awarded an A grade or higher this year.

Analysis of entries by exams regulator Ofqual found that 70.1% of pupils at fee-paying schools achieved the top grades, compared with 44% in 2019, when exams last took place, and 60.8% last year.

Overall, the proportion of A-level entries awarded an A grade or higher has risen to an all-time high after exams were cancelled for a second year due to the pandemic.

However, independent schools have seen the largest absolute increase in the highest grades compared with other types of schools and colleges – up 9.3 percentage points on last year.

Some 41.9% of students at academies achieved A or A* grades this year, a 5.7 percentage point increase from last year, while for comprehensives it was 39.3%, a 6.2 percentage point rise.

While private schools saw a larger absolute increase in top grades, Ofqual said the relative change between the independent and state sector was less stark, as fee-paying schools started from a higher base rate of top grades.

In relative terms compared with 2020, Ofqual said independent schools saw an increase of 15.2%, while it was 15.8% for academies and 18.7% for comprehensives.

Ofqual said outcomes for all types of schools and colleges have increased compared with last year, but the extent of this “may partly reflect longstanding differences in the distribution of grades for different centre types”.

A report by the exams regulator published on Tuesday’s A-level results day said: “For example, in normal years, the distribution of grades for students attending independent centres is clustered around the top grades.

“A uniform increase in grades awarded across all types of school and college is therefore most likely to benefit students attending independent schools at the top grades.

“For other centre types, the impact of increased grades may be lower down the grade distribution – wherever most of their candidates are normally clustered.”

But educational charity The Sutton Trust said the coronavirus crisis has “compounded existing inequalities and today’s results are a reflection of that”.

Founder and chairman Sir Peter Lampl said: “Since March 2020, our research has consistently shown how much harder state schools – particularly those in less affluent areas – have been hit by the pandemic.

“The pandemic has compounded existing inequalities and today’s results are a reflection of that.

“We’re seeing growing gaps between independent and state schools at the top grades. This poses an immediate challenge for university admissions.

“While it’s encouraging to see more students from less affluent areas going to university this year, it’s of real concern that the gap between those from less affluent areas and those from well-off areas has grown.

“Given that disrupted learning has affected lower income youngsters more, we urge universities to give additional consideration to disadvantaged students.”

In a separate analysis published by Ofqual, the regulator measured how grades had compared between different groups, with variables including ethnicity and free school meal (FSM) eligibility.

Ofqual said that of the “many between-group comparisons examined in our modelling”, the majority showed “no notable change” from 2020 to 2021 or from 2019 to 2021.

However, as first reported by Tes (formerly the Times Education Supplement), the report said that the attainment gap for pupils on FSM, black candidates and those with a very high level of deprivation achieving grade A or higher had widened between 2019 and 2021.

Conservative MP Robert Halfon, chair of the Commons Education Committee, told BBC Radio 4’s World at One programme that the last year “has been nothing short of a national disaster for our disadvantaged pupils”.

Lee Elliot Major, professor of social mobility at the University of Exeter, added: “The Government urgently needs to set out its plans for a return to a national exam system from next year that is fair to all pupils irrespective of what school they attend or home they come from.

“The race for places on the most popular degree courses will intensify to unprecedented levels amid this year’s steep rise in A and A* grades. Demand for higher education will increase at a time when jobs are harder to come by.

“Unless universities up their game, we could see social mobility put back years. Our research has shown that poorer pupils have suffered disproportionate learning losses during the pandemic.”