Independent school leaders are “gravely concerned about the individual tragedies” buried in A-Level exam results data this year.

Ian Power, general secretary of the HMC group of leading independent schools said that while overall statistics looked “encouraging” for independent schools on the surface, “the right students are not necessarily getting the right results.”

He spoke as exam regulator Ofqual has been accused of offering an advantage to some independent schools through its computer algorithm used to moderate teacher-predicted A-Level results this year.

Exams were cancelled in the spring because of the Covid lockdown and exam regulators Ofqual devised the system to ensure potential grade inflation was kept to a minimum.

Overall figures suggest that students in schools and colleges with large cohorts were more likely to be marked down than students in institutions with small cohorts – something common in many independent schools.

The percentage of students getting As and A* grades in private institutions is up 4.7 points since 2019.

The HMC carried out a snap poll, however, which revealed 81 per cent of heads believe this year’s results are unfair.

Only 19 per cent believe they are fair and 94.5 per cent have subjects in which the awarded grades are significantly below the centre assessment grades.

A total of 37 per cent of heads said their pupils are experiencing more difficulty than normal in getting into university.

Mr Power said: “HMC is gravely concerned about the individual tragedies lying buried in the data this year. Our members are telling us that whilst the overall statistics might look encouraging on the surface, the right students are not necessarily getting the right results.

“We have heard of students marked down by two or more grades to results which bear no relation to their previous record. The futures of young people from all sorts of backgrounds in every type of school are being put at risk and we are as frustrated and confused as colleagues in the state sector.

“Too many pupils are left with little idea about why this has happened, how to appeal, whether their particular mock exams will be admissible, and whether a system which has already let them down will be too slow to allow them to move on this Autumn. Heads are working tirelessly to get them answers which are not yet forthcoming.

“These are the same young people who were told by the government that everything would be done to help them move on to their next stage in life. We have supported the attempts by the regulator to design a robust model under challenging circumstances, but it hasn’t worked well enough.

“The appeals system must be sorted out immediately so pupils can move on and schools can turn their attention to a safe and happy start to the new school year. “The government must move fast to ensure the Covid generation is not further punished.”

Outrage over exam results in Scotland, which were released nearly two weeks ago, resulted in the Scottish government ditching its moderation process and using only teacher-predicted grades, after thousands of students were marked down.