A Manchester boys' school has dropped maths GCSE from its curriculum in favour of another qualification which it regards as more challenging.
The IGCSE does not include coursework
Students at the independent Manchester Grammar School, in Fallowfield, will sit the International GCSE, sat by pupils overseas, next year.
Highmaster Christopher Ray said the IGCSE did not include coursework, which brighter students found tedious.
He said: "Some GCSEs do not appear to be appropriate for the most able."
Eighty-nine per cent of pupils at the school achieved grade A or A* in the maths GCSE last year.
Ruth Lea, director of the think-tank Centre for Policy Studies, said: "GCSE is nothing like the standard of O-level.
"I'm not surprised they are turning their backs on the GCSE because it's easy."
Mr Ray said: "I would say most schools who are thinking about IGCSEs are prompted by a desire to do a coursework-free option."
He added: "We wanted the coursework-free option because the coursework that's demanded for GCSE maths is very routine and very undemanding.
"When you are dealing with able young men, as we are, you want something that will challenge them."
Edexcel is an examining body that offers the IGCSE.
It says it has been surprised by the level of interest in the qualification from schools in England because it is only marketed overseas.
But it is not a realistic option for state schools in the UK because it is not on the list of officially accredited qualifications.
This means they could offer it - but would not receive government funding to teach it and students' results would not be recognised in the performance tables.