Tens of thousands of pupils in England awaiting their A-level and GCSE results can “feel satisfied” their grades are fair despite exams being cancelled for the second straight year, according to the head of the exams watchdog.

Pupils are set to receive their A-level results on Tuesday and GCSE results on Thursday, with grades determined by teachers, rather than exams, as they will only be assessed on what they have been taught during the pandemic.

Ofqual interim chief regulator Simon Lebus told the BBC that the watchdog wanted to create a system where every student was given a fair chance to show what they can do.

“I’m very confident that, when they get their grades on Tuesday and Thursday this week, they’ll be able to feel satisfied that that’s happened,” he told the broadcaster.

Mr Lebus said there have been three stages of checks to ensure students can feel they have been “fairly treated”, including Ofqual checking the policies that schools have for awarding grades and exam boards looking over them.

Asked why this system may see slightly more generous grading than a normal exam year, he said: “I think a good way to think of it is exams are a bit like a snapshot, a photograph – you capture an instant, it’s a form of sampling – whereas teacher assessment, it allows teachers to observe student performance over a much longer period, in a rather more complex way, taking into account lots of different pieces of work and arriving at a holistic judgment.

“I think, from that point of view, we can feel satisfied that it’s likely to give a much more accurate and substantial reflection of what their students are capable of achieving.”

Teachers in England have been required to consider a range of evidence, including mock exams, coursework, and in-class assessments using questions from exam boards, to make decisions on pupils’ grades.

Headteachers had to submit a personal declaration that they believed grades to be accurate.

Schools and colleges were asked to provide samples of student work to exam boards, as well as evidence used to determine the grades for the students selected, as part of quality assurance (QA) checks.

It came after Sir Keir Starmer warned that “chaos and incompetence” in Government had created extra stress for those awaiting their results.

The Labour leader said Prime Minister Boris Johnson and Education Secretary Gavin Williamson had failed to act early enough to ensure this summer’s results operations run smoothly.

It frustrates me immensely that this week's big moment in so many young people's lives is being risked by the chaos and incompetence at the top of this Government

“It frustrates me immensely that this week’s big moment in so many young people’s lives is being risked by the chaos and incompetence at the top of this Government,” he said.

Last summer, the fiasco around grading led to thousands of A-level students having their results downgraded from school estimates by what Mr Johnson dubbed a “mutant algorithm”, before Ofqual announced a U-turn.

This year there will not be an algorithm used to moderate grades.

The Department for Education said it recognises the “unprecedented challenges pupils and students have faced” during the pandemic and that a “rigorous system to ensure grades are fair” has been put in place.