Last week, Grange school, in Oldham, which serves three of the most deprived council wards in England, celebrated coming near the top of GCSE league tables on two important measures.

It was ranked England’s fourth most improved secondary, the proportion of pupils achieving five or more good passes in GCSE or vocational equivalent having soared from 33 per cent in 2002 to 72 per cent last year. And it was listed as sixth best secondary for “value-added” - the progress pupils make between 11 and 16.

In 2004, the specialist school was proud to announce it was the best visual arts college in England for value-added results.

But, after The TES assessed the impact of a new measure being used in the tables from next year - that the good passes must include English and maths - Grange tumbled down the rankings. Its results are now nearer to what might be expected, given local deprivation and the fact that 99 per cent of its pupils have English as second language.

Grange had 13 per cent of its pupils achieving five Cs or better, including English and maths, in 2005. That kind of change, which many other schools will experience next year, places yet more attention on the influence of GNVQs in the current statistics.

Of the school’s 155 Year 11 pupils last year, only 24, or 15 per cent, got a C or better in maths GCSE. For English, the figure was 33 per cent. The school had 136 GNVQ entries, in ICT, art and design and science, each of which had impressive pass rates.

So is the Grange really not that good? And has the school cynically used GNVQs to boost its position? Mr Hollinshead has some impressive statistics that refute these suggestions and Ofsted was impressed when it visited in 2002.

Grange’s results on the new measure are broadly in line with detailed data analysis which predicts pupils’ likely GCSE grades, given their starting points at 11. Exam results for 2005 confirm that youngsters were entered for every major academic subject.

And Mr Hollinshead said vocational courses had helped the college improve its post-16 staying-on rates dramatically in recent years.

In 1993, only 20 pupils transferred to Oldham sixth form college. By 2004, after the introduction of vocational courses, this had increased to 77. Of these, around 80 per cent go on to university, he said. This, he said, is the proof of the courses’ worth. He bristled at the suggestion that some schools have used GNVQs to inflate their table positions. He said: “It is not Grange school that has decided to produce the league tables in this way. We are doing the right thing for our pupils in our school.”

Nick Brown, Oldham sixth-form college principal, backed Mr Hollinshead enthusiastically. He said Grange was helping to improve pupils’ aspirations in an area where traditionally hardly anyone went to university.

But the effect of GNVQs on the scores of those schools set to plunge down the league tables seems indisputable. It is given further weight by taking another look at Grange’s detailed results. The school’s 30 top-set science pupils were entered for double science GCSE. Sixteen, or 53 per cent, got a C or better. Some 44 pupils below the top set took GNVQ science. Forty, or 91 per cent, passed.

It is hard to avoid the impression that the GNVQ is easier than GCSE. Mr Brown said that he was unclear of the value of GNVQs to pupils. He said: “I would rather accept someone (into the college) who had three GCSEs, in English, maths and science, at A*-C rather than someone with a stack of vocational qualifications.”

However, with many pupils now taking more than eight GCSEs, it is likely results in subjects other than maths and English have helped to drag up scores on the old measure.

Nationally, maths results are the worst of any major subject, making it inevitable that changing the measure to always include the subject would drag down scores for many schools.

Many schools will rise up the rankings as their new score is very similar to their old one. Coloma Convent girls’ comprehensive in Croydon, south London, scored 89 per cent on both measures.

Head Maureen Martin said: “I’m pleased that our girls do well in English and maths, but I’m not that concerned about league tables. There are so many things they cannot measure.”

* Some of England’s most famous public schools, including Winchester and Dulwich College, will come bottom of the tables on the new measure because they entered no pupils for English or maths GCSE. Students take international GCSEs instead.