Local authorities serving some of England's toughest areas are emerging as the biggest losers after the introduction of a new GCSE league table measure two years ago.
Of those authorities serving poor areas, some are doing relatively well on the old rankings, which focus on pupils gaining five GCSE A*-Cs overall. But they plummet down the tables under the new indicator.
Since 2006, schools and councils have been ranked on the proportion of their pupils achieving five good grades including English and maths. This has replaced the five GCSEs in any subject indicator, although these results are still published.
Analysis of this year's rankings on the two different measures reveals stark differences. St Helens in Lancashire, is the biggest loser, plunging 105 places down the table of 149 councils. This year, 67.5 per cent of its pupils achieved five good GCSEs overall, which ranked it 32nd. But fewer than half achieved C grades or better in both English and maths, so its percentage on the new measure was only 37.4, ranking it 137th.
Other big losers are Hartlepool, Newcastle upon Tyne, Gateshead and Liverpool, all of which slide more than 50 places. By contrast, richer Enfield, Bracknell Forest, Richmond upon Thames and Norfolk are big winners.
The differences indicate that maths and English remain stumbling blocks for many schools serving poor areas.
They may also highlight the effect of courses such as Btecs and OCR nationals, which are considered to be worth four GCSEs in league table terms. Under the old measure, these qualifications levelled the playing field between schools serving richer and poorer areas, but they are less of a factor under the new one.
The overall results saw 47.2 per cent of pupils achieving five good GCSEs including English and maths - an improvement of 0.9 percentage points, and a new record. On the old measure, the improvement was more pronounced, increasing 3.2 per cent.