The number of students scoring top A-level results has risen for the first time in six years.
More than one in four students got at least an A grade this year - the first time the pass rate has risen since 2011.
But the number of pupils taking up university places has dropped, with many places still open.
This is the first year A-levels and GCSEs were subject to a new marking system.
This means a shift away from coursework and modular exams for A-level students.
There was a 42% drop in the number of students taking AS level exams as they no longer count towards the final A-Level results.
GCSE marking systems in England have also been changed to numbers rather than grades, with the new system being fully implemented by 2020.
The changes were introduced to match other countries and to "keep pace with universities' and employers' demands", exams regulator Ofqual said.
But a "small number" of A-level results were withheld by regulators over allegations of a paper leak.
Some students are believed to have possibly accessed an internet forum containing information about an end-of-year maths and economics exam.
The schools and pupils in question have not been identified.
Pupils who took their exams in the wake of the Grenfell Tower tragedy will have their grades reviewed to ensure their higher education prospects are not compromised.
Kensington and Chelsea Council said it would work with schools and exam boards to identify pupils affected and have their grades "looked at, reviewed and modified accordingly if necessary".
Councillor Elizabeth Campbell said: "We know that some pupils took exams following the night of the fire and in the days afterwards, and I want to ensure that their chances of a university or sixth form place are not impacted by something totally out of their control."
Meanwhile, the mother of Manchester Arena bombing victim Georgina Callander revealed her daughter had won a place at university.
The 18-year-old from Lancashire had hoped to become a paediatrician - her dream since she was 11.
Her mum Lesley said the family were "so proud".
And Nobel Peace Prize winner Malala Yousafzai is heading to Oxford after being getting her A-level results.
The 20-year-old, who almost died after being shot in the head by the Taliban, did not reveal what grades she got.
But she revealed she had got into prestigious Oxford on Twitter.