It is an unusual boast, but Swansea’s schools have some of the worst and the best GCSE results in Wales.

Despite this polarity, the authority’s pupils performed well at both key stage 3 and GCSE in the latest value-added figures that take free school meal entitlement into account.

Robert Barber, head of service for school improvement, puts this down to a “strong ownership” of improvement within the authority’s schools.

“We’re using data to help schools analyse where their strengths are and where they need to develop,” said Mr Barber.

“It’s not just a case of one size fits all.”

In Swansea last summer, the proportion of pupils who gained five or more A*-C GCSE grades was 5 percentage points higher than expected at 51 per cent, when taking free meals into account.

Results were also 5 percentage points higher than expected at KS3, with 57 per cent of 14-year-olds achieving the level expected for their age in the core subjects of EnglishWelsh, maths and science. These results placed the authority third out of 22 in Wales, for value-added performance.

At one end of the Swansea spectrum is Bishopston comprehensive, where 82 per cent of pupils achieved at least five or more A*-C grades at GCSE in 2005. Only 5 per cent of its 1,090 pupils were entitled to free school meals.

At the other is Dylan Thomas community school, where just 15 per cent gained five good GCSEs in 2005. Some 64 per cent of pupils were entitled to free meals last year, the highest figure in Wales.

Some local education authority improvement initiatives apply to all schools, such as an emphasis on inclusion and engagement that is behind the deployment of teachers trained to work with dyslexia in every school. The same approach has led to a wide choice of vocational subjects at KS4.

But the authority prides itself on its bespoke response. At Pentrehafod high, which has a number of asylum-seeker children, it will introduce the ethnic-minority language service.

At Bishopston, the emphasis will be on building on the good results to avoid complacency, said Mr Barber. “The key person is always the headteacher.”

David Jenkins has just completed his first year as head at Pentrehafod high, and is determined to push up attainment. Last year 34 per cent of pupils gained five good GCSEs, and free meal entitlement was 23.5 per cent.

The Wales average is 18 per cent.

“My aim is to get to 40 per cent (at five good GCSEs),” he said.

“We’re very determined to raise standards. We have youngsters from many backgrounds and we want to ensure each youngster realises their potential.”

He says the school benefits from a strong partnership with the LEA. Together they set targets, collaborate on good practice and work on self-evaluation.

At Pontarddulais comprehensive, head John Radford credits a credo of teaching, learning and standards, which is also at the heart of transition work with primary schools.

“It’s all about achievement and attainment,” said Mr Radford. “We seek a broad base of achievement in things like drama and music and the school council. But we never forget the reason why children are here, to maximise their potential and qualifications.”

Ian Thompson recently joined Bishopston as head after holding the deputy post at Morriston comprehensive school, where close to one in two pupils achieves good GCSEs.

He recognises that it is often forces beyond a school’s control that dictate results.

“It’s obviously more difficult in some areas to achieve higher results because of less support away from school. I think that’s the biggest factor.”

Funding is an issue. Last year Pentrehafod cut five staff. “We have had some good results but it’s hard work to make sure this continues in future,” added Mr Barber.

Assembly government statistics published last month show a clear relationship between deprivation - as measured by entitlement to free school meals - and academic achievement in Wales. As one rises, the other falls.

Statisticians used FSM entitlement to calculate what children in each LEA would be expected to achieve, and compared it with their actual results.

Children in Neath Port Talbot, Carmarthenshire and Swansea achieved well above expectations at GCSE. At KS3, the top-performing “value-added” areas were Merthyr Tydfil, Neath Port Talbot and Swansea.

Academic achievement and entitlement to free school meals 2005, see new.wales.gov.uk