School performance league tables due to be published this week will be 'meaningless' and 'ridiculous' following last summer's 'corrputed' English GCSE results, according to the region's headteachers.

League tables have never been popular among headteachers.

But following last year's widely-criticised inconsistencies with an English GCSE assessment, the secondary school statistics due to be published on Thursday will be even more likely than usual to get their blood boiling.

'Meaningless,' 'corrupted' and 'ridiculous' are just some of the words used by Norfolk education leaders last night as they waited to see what effect the problems would have on their schools' positions.

A total of 475 Norfolk students are thought to have missed out on an all-important C in English after grade boundaries on a controlled assessment were altered between the January and June assessment periods last year.

While a number of the region's schools saw a big drop in the proportion of its pupils achieving at least a C in English this summer, others saw little or no change.

With the Department for Education's annual performance tables focusing so heavily of the percentage of pupils achieving at least five A* to C grades including English and maths – the so-called gold standard – schools are likely to find their positions in the national standings greatly affected by whether they chose to put students in for the January or June assessments.

Brian Conway (pictured) headteacher at Notre Dame High School, whose headline results were about 15pc below their expected levels because of plummeting English results, had strong feelings about the reliability of this year's tables.

He said: 'I don't believe in league tables – and even more so in the light of the English GCSE debacle.

'I would caution people against putting absolutely any validity on the league tables this year. In a normal year they are the kind of things I ignore.

'This year, I would think they are ridiculous. They are just there as nonsense.'

Last year, Norfolk fell further down the overall performance tables with its schools' results putting it in 115th place out of 151 local authority areas when it came to achievements at GCSE level.

That masked a large number of record performances for many secondary schools and the biggest improvement overall for six years.

But with this year's tables it will be very difficult to tell if efforts to make further improvements and try to reverse that decline in the national standings has had any impact.

Peter Devonish, headteacher at Dereham Neatherd High School, has previously spoken out about the GCSE English problems.

He said: 'This summer the results are fairly meaningless because of the GCSE fiasco. It has skewed all the results for schools all over the county – all over the country. It's the gold standard and the value added that are both impacted upon.'

Many parents look to the tables to tell them how well schools in their area are performing and can even use them to decide which sites to send their children to.

At a time when the number of secondary school-aged children is decreasing and headteachers find themselves having to compete to get pupils on the school roll, they could do without league tables which they feel are inaccurate.

Peter Whear, headteacher at Old Buckenham High School which chose to withhold its figures from the EDP's GCSE coverage this summer, said the English results were 'fundamentally corrupted' and that should be taken into account when looking at the league tables.

He added: 'Parents have the right to information that is transparent and accurate. Students taking GCSE exams deserve to be treated equally. The present system provides neither of those guarantees.'

An investigation by exams watchdog Ofqual last year acknowledged there had been inconsistencies in the way papers had been marked between January and June – but blamed over-marking by teachers in internal controlled assessments for the need to change the grade boundaries.

Glenys Stacey, of Ofqual, said: 'Overall, the grading of GCSE English in the summer of 2012 was a fair reflection of the performance of pupils as a whole.

'However, within the overall picture, some schools experienced significant variations.'

The regulators' report also raised concerns about how much emphasis the government put on the English results for its performance measures.

It said: 'The regulator concludes that so much weight on one grade in one subject as part of accountability and performance measures created perverse incentives for schools in the way they marked controlled assessment and led to the over-marking.'

A judicial review into the grading problems, brought about by a legal challenge by unions and headteachers from across the country, has yet to be completed.

Neatherd headteacher Mr Devonish said: 'The longer it takes, the more complex they must be finding it to unpick everything.'

Mr Whear added: 'This ruling is now expected on January 28 and may result in the re-grading of many thousands of GCSEs. This would have a huge impact on the accuracy of the published figures in the league tables.'

The DfE said concerns about this year's league tables in the light of the English GCSE problems was a matter for Ofqual and not ministers.