High schools and academies across Suffolk are digesting some of the most volatile GCSE results seen since the exam was introduced in the mid-1980s.

Some schools saw considerable improvements in earlier years’ results – but at others there was a significant drop in performance.

This was reflecting national volatility – combined with a change in the way exams are sat. They are now concentrated at the end of the two-year course.

Overall across Suffolk there was a slight increase in the number of students who gained five A*-C grade GCSEs including English and Maths, the figure went up by 1%.

However individual schools showed widely varying results – and several schools, including Felixstowe Academy, are planning to challenge the marks, especially for English.

Hadleigh High School showed a massive improvement in results – the number of students gaining five or more good A*-C GCSEs including English and Maths went up from 44% last year to 69%, an increase of 25%.

However some traditionally-successful schools like Debenham High and Thomas Mills High at Framlingham saw their figures fall significantly.

Hadleigh High headteacher Caroline Gibson said: “We are absolutely delighted that all the efforts made by pupils and staff have paid off in a time where examinations are in a state of constant flux.

“These successful outcomes, along-side the effective skills for learning we value and develop, will place our pupils in a strong position for the next phase of their learning.”

Across the county 56% of Suffolk’s year 11s got the expected level of attainment. In 2013, it was 55%.

Another school with impressive results was Westbourne Academy in Ipswich – 52% of students achieved five or more A*-C grades (including English and Maths). This is up from 31% last year, an increase of 21%.

Lisa Chambers, Suffolk’s cabinet member for education, said: “Early indications are that there’s been a rise in the number of GCSE students gaining five or more good A*-C grades, including English and Maths.

“This is testament to the hard work and dedication of teachers, heads, governors, parents and, most importantly, students.

“National changes to the way exams are taken, papers are marked and results recorded, seem to be affecting Suffolk too – but this doesn’t take away from the positive picture that we’re seeing today.

“We will continue to work with, and challenge, schools to drive up educational attainment. That is the direction we set with our Raising the Bar agenda and is now what education professionals across the county are united around.”

Suffolk NUT secretary Graham White said his members would be feeling let down because the changes made it very difficult to judge the success of students.

He said: “We have seen changes brought in without consultation, and now we see that in English there have been major changes forced on teachers which have really changed the way the examinations are held.”

He feared that employers could find it difficult to judge the potential of students after this year’s exams.