The proportion of Norfolk teenagers who achieved the government's GCSE gold standard has remained static in a year which saw a sharp fall in English results across the country.
The news came as thousands of students across the region yesterday celebrated their GCSE results, with some schools posting a significant improvement in results.
Data collected from schools by Norfolk County Council had forecast 60pc of pupils would gain at least five GCSEs at A*-C, including English and maths.
That would have equalled last year's national average, but provisional results collated yesterday showed the figure for 2014 remained at 54pc.
• See our full coverage of GCSE results day here
• Map of GCSE results in our region
• GCSE results - school by school
Brian Conway, chairman of Norfolk Secondary Education Leaders and headteacher of Notre Dame High School in Norwich, said: 'Norfolk schools' early results seem to reflect the national picture of significant volatility. Several schools have indicated that they will be challenging their grades and some have felt the impact of changes to the exam system.
'Despite this, more than half of the county's schools are seeing improved results, which looks to be a considerable achievement, given the turbulence that has been reported.'
Suffolk County Council said provisional results from four out of five secondary schools suggested a 1 percentage point rise in the proportion of its 16-year-olds achieving the gold standard, increasing from 55pc last year to 56pc this year.
Andrew Hine, headteacher of Benjamin Britten High School in Lowestoft, which suffered a 10 percentage point drop in pupils gaining the gold standard, said: 'Earlier this week, the exams authority warned about 'grade volatility', and the exam board notified us yesterday of changes to the mark moderation process.
'This change has had an impact on students here, and in particular on their English results.
'English results have been depressed by the exam board moderation and grade boundary setting process.
'We do not believe we have an accurate reflection of our students' abilities in English this year and have already commenced a challenge to the marks awarded by the exam board.'
City Academy Norwich in Earlham, Norwich, where 22pc of pupils gained the gold standard last year, refused to make this year's results public until it knew the results of what is said was a large number of appeals.
The results reported by many schools now may be higher than those that will appear in league tables next January, because the official tables will, for the first time, exclude results of exams that pupils re-sat. The Norfolk figure of 54pc includes re-sits.
Results improved in Norwich, which in June was named the worst-performing local authority area in England in 2013.
The city saw the biggest improvement in Norfolk, with a 4.3 percentage point boost in the proportion of children achieving the gold standard from 46.2pc to 50.5pc.
The Open Academy in Heartsease, Norwich, saw a record 47pc of pupils gain the gold standard, rebounding from last year when its 34pc figure saw it fall below the government's floor standard of 40pc.
Other schools that posted a big increase in results included Archbishop Sancroft High in Harleston, Caister High, Cliff Park Ormiston Academy in Gorleston, Hellesdon High, Old Buckenham High, and Thetford Academy.
Schools that fell below the 40pc floor this year included East Point Academy and Ormiston Denes Academy, both in Lowestoft.
Earlier this month, Ofsted inspectors praised Norfolk County Council's support for school improvement as 'effective', compared to 'ineffective' the year before.
James Joyce, chairman of the children's services committee, said: 'This is the end of the first year of our very ambitious strategy to support and challenge school improvement and we knew there would not be a major shift in performance in GCSE in year one – because these are two year courses.
'We do remain concerned about the performance of some schools and are analysing the data closely to see where we need to focus more attention.
'We will be making contact with those whose performance is unacceptably low because this will have an impact on the future of their students.'
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