Hertfordshire has posted the highest average for GCSE results across the East of England in new league tables, although the validity of the data has been questioned.

League tables released by the government last week shows 73.2 per cent of students studying in the county achieved five or more GCSEs at A*-C, with 66.4 per cent managing the same but including English and maths.

That figure is 13 per cent above the national average – 53.4 per cent – but more than a third of the secondary schools based in Stevenage and North Herts recorded results below that number.

Nationally figures have dropped after a government decision to only count a pupil’s first attempt at an EBacc qualification – consisting of English, maths, history or geography, the sciences or a language – and stop so-called ‘poor-quality’ vocational qualifications being counted.

The internationally used IGCSEs have also been omitted, with the independent Princess Helena College in Preston deciding not to submit its results as a result.

Headteacher Jo-Anne Duncan said: “Our GCSE results are very strong with 51 per cent of all exams passed at either A* or A, and 100 per cent of girls achieving five A*-C grades including English and maths. However, the government’s new system for rankings excludes the IGCSE exams, which we use for certain subjects.

“We believe that these offer a more rigorous course and a better level of preparation for A-levels, and it is disappointing that they are not recognised in the league tables.”

Barnwell head Tony Fitzpatrick, who is also the chairman of the Stevenage Educational Trust, said: “What the tables are not doing is comparing like for like with previous years.

“It’s important schools share performance data with parents but it needs to be treated with caution.

“Parents need to look at the school’s website and visit to get a real feel for the place. I believe a broad and balanced curriculum which meets the needs of the students is what is required.

“The changes narrow the curriculum which I think is a shame – and schools now have a decision to make whether they offer subjects and qualifications which are not recorded in the performance tables.”

Councillor Chris Hayward, who is responsible for education and skills at Herts County Council, has praised schools for their efforts.

He said: “We are immensely proud of the achievements of our young people and the teachers who have helped them achieve success in their recent exams.

“It really is a credit to everyone involved in education in Hertfordshire that our schools continue to be among the best in the country.”