A mixed picture has emerged as thousands of pupils opened their A-level results across Northern Ireland.

The results, based on predicted grades and past performance after the coronavirus pandemic caused final exams to be cancelled, saw the overall pass rate of pupils achieving an A*-E grade rise by 0.8% to 99.1%.

However, 37% of estimated grades were lowered and 5.3% were raised.

Some schools have hit out after some pupils received lower grades than they had expected.

Bangor Academy principal Matthew Pitts said 63.4% of his school's grades had been lowered while Alan Hutchinson, from Glastry College, said 56% of their grades had been reduced.

St Cecilia's College principal Martine Mulhern said 13% of grades at her school at A2 level were lower than the AS grades.

Other schools have expressed general satisfaction at results issued.

Olwen Black, vice principal of Belfast Boys Model School told the PA news agency that there had been no surprises among results at the school.

"I'm glad to say this morning that we are delighted with the results for the boys. This cohort have done tremendously well as their predecessors had and there have been no surprises there," she said.

"We have 74% have got A-C grades, and they will take the boys where they hoped so for us this is a good morning."

She described the school year as having been the most unusual amid the coronavirus pandemic and an anxious time leading up to the results after events in Scotland, adding staff were working to support the boys throughout.

Deputy head boy Ethan Shaw studied History, Politics and Journalism, and was content to receive the grades he needs to go on to study Politics at Ulster University.

"I remember watching the news and it was difficult to comprehend, trying to figure out how the grades system would be applied," he said.

"With everything, it is strange to be walking through the school doors for the first time in six months but also the last time. It has been a chaotic year."

Across the city at Our Lady and St Patrick's College, Knock, pupils referred to discrepancies in results issued.

Maria McCann said she was content that she had received the grades she needed in Biology, Chemistry and French to be accepted at Queen's University to study medicine.

"I know it has been a very stressful five or six months for everybody, especially in the last couple of weeks it has been quite hard on people," she said.

"Thankfully for me it worked out in the end but I know there has been a lot of discrepancies and hopefully that will be sorted out in the coming days.

"I got the grades that I needed to get."

Fionnula Murtagh studied Biology, Chemistry and Maths and has secured a university place in Glasgow to study Veterinary Medicine.

"It's surreal to be back in school, seeing all my teachers' faces again but it's been nice," she said.

"I've missed school, it's been really strange being away and I think it is going to be quite difficult to get back into the routine of learning."