Wide differences in GCSE performance between similar schools in Bradford are not acceptable, an education chief claimed today.

As today's exclusive survey shows, a massive gulf separates Bradford's highest-flying comprehensives from those with lower scores. While this is often explained by difference in intakes, there is concern that some schools are under-performing.

Councillor David Ward, executive member for education, said: "When you look at the remarkable improvement some schools have made, it shows anything is possible. The priority for next year is additional support to those schools which are under-performing to ensure they produce an equivalent improvement in the future. No school is beyond help."

Nineteen of the 28 secondary schools either improved their results or stayed the same this year. Schools where GCSE results have got better every year since 1999 include Bradford Cathedral in East Bowling, Holy Family RC at Keighley and Queensbury School.

At Bradford Cathedral, a school placed in special measures by Ofsted, results have risen dramatically from a low point when only two per cent of school leavers had five A*-C grades. Since then the school's results have improved to 22 per cent reaching that standard. Head teacher David Brett said: "These results are the highest ever."

Ilkley and Bingley Grammar schools have again maintained their position at the top of the list of Bradford's LEA comprehensives. After them come two of the district's Roman Catholic schools, Holy Family and the all-girls St Joseph's, and relative newcomer Feversham College, the Muslim girls' school, which put in another strong showing, improving its GCSE score to 60.

Schools showing the most dramatic improvements since last year are Salt Grammar and Laisterdyke High.

There is a very strong correlation between GCSE results and poverty in the local community. Of the ten Bradford schools with the highest results, eight of them also have the lowest number of children on free school meals. However Feversham (38 per cent on free school meals) and Beckfoot (18 per cent) buck the trend by finishing in the top ten.