The achievements of many teenagers in passing more than a dozen GCSEs have raised concerns that many pupils are studying too many subjects.
Lorna Anne Mullan was one teenager who passed 16 GCSEs
Exceptional students have been taking as many as 16 GCSEs.
John Cairns, head of Brighton College, said sitting so many exams was "quite unnecessary" and promised to limit his pupils to nine subjects from next year.
"League tables based on point scores are encouraging heads to enter pupils for exam after exam," he said.
Lorna Anne Mullan, a pupil at Kenton school in Newcastle, passed 16 GCSEs and put her success down to hard work and being interested in the subjects.
The 16-year-old said: "I was expecting to do well but not to get 11 A*s and five As.
Andre Buckley's favourite subject is information technology
"A lot of it is down to hard work but you have to enjoy the subjects and, I suppose, have a talent for them as well."
Lorna's classmate, Sarah Crosby, also managed a haul of 16 GCSEs - three A*s, 10 As and three Bs.
She had the added honour of being one of the top five in the country in English literature.
"I've always loved reading and have read a lot since being little," she said.
"I had a feeling I had done well but did not think it was that well and to be in the top five nationally is great."
'A little surreal'
Lucy Du achieved some of the best results in the country with 13 A* grades and one A - as well as an A in AS-level maths, the first half of an A-level.
The 16-year-old, from Beckton, east London, said she was "overwhelmed, extremely happy and quite proud".
She said she found the exams "quite hard".
"They are challenging to revise for and prepare for," she said.
Devon schoolgirl Rose Hall achieved the perfect score in her GCSEs, with 12 A* grades.
Although she was delighted with her results, the 16-year-old from Lympstone said she found all the attention "a little bit surreal".
Among thousands of contented GCSE students was Princess Eugenie, 16, daughter of the Duchess of York and Prince Andrew, scored two A*s, four As and three Bs.
A royal spokeswoman said the princess, who had been studying at Marlborough College in Wiltshire, was "very relieved and happy" with the results.
"Her parents are very proud," said the spokeswoman, adding that Eugenie was celebrating in Spain with her mother, elder sister Beatrice and school friends.
Actress Emma Watson - Hermione Granger in the Harry Potter films - lived up to her Hogwarts persona by achieving eight A*s and two As despite having had to combine studying and filming.
Meanwhile, six-year-old twins Peter and Paula Imafidon from east London became some of the youngest children to pass GCSEs.
The pair, from east London, managed G grades in statistics. Paula went one better in maths with an F - Peter getting another G.
They attend a state school in Waltham Forest, but were given extra lessons at a centre run by the Excellence in Education group.
They said the exams were "easy" because they liked "to do adding and subtracting".
Paula explained that they became interested in maths after hearing their older siblings talking about numbers.
Sister Samantha passed two exams last year, when she was just seven.
The Wilkinson family from Portsmouth were also celebrating after triplets Danielle, Samantha and Andrew achieved 36 GCSEs between them.
Included in their haul were 16 A* grades, 16 As and four Bs - attained at Portsmouth's Springfield School.
The trio, aged 16, said that sibling rivalry kept them focused and helped them work hard to achieve their grades.
Danielle, who wants to work in forensic science, said: "There's a lot of competition between us - we all have to do better than each other, so we end up doing really well."
The twins' elder sister passed a GCSE when she was seven
One of the youngest pupils to succeed was seven-year-old Andre Buckley from Watford, who scored a grade B in information technology.
Football fan Andre said said: "I get to use a computer and I like using computers. I like playing games on the internet and sending e-mails."
Andre praised his teachers at Ryde Teaching Services, an education centre in Bushey, Herts, where many young children study for exams.
Eight-year-old Amar Patel, who also studied at Ryde, achieved a C grade in information technology.
His 12-year-old sister Alisha scored a B in the same subject.