By Gary Eason
Education correspondent, BBC News
League tables show more than how hard pupils and teachers work
This year's secondary school league tables for England expose those schools that are struggling to meet even the basic target set by ministers - 30% of pupils getting the equivalent of five good GCSEs.
But they also highlight a range of other performance data.
At GCSE level the tables contain information on some 4,083 schools, including 3,427 state schools, and there was 100% attainment in 100 of them.
That is, all the pupils recorded as having taken their GCSE and equivalent qualifications last year achieved at least five at a grade C or above, including both English and maths GCSEs.
The "best" this year at this level was Invicta Grammar School in Maidstone, Kent, on the basis that its pupils averaged more points than those in any other school.
They accrued 764.5 points apiece, using the tariff established by the Qualifications and Curriculum Development Agency (QCDA).
Prepare for future
For example, an A* grade in a chemistry GCSE is 58 points; a merit award in a BTec First Diploma in applied science is 184.
Controversially, points are not awarded for International GCSEs which are offered in a growing number of subjects by a growing number of schools in the independent sector, which regard them as more rigorous qualifications.
The effect is that some excellent private schools appear to perform very badly on the government's standard benchmark.
The worst school this year was St Peter's Church of England in Chelmsford, Essex - where only 8% made the grade, averaging 214.9 points.
The head teacher, Kulvinder Cheema, said St Peter's was committed to ensuring that all students had the best education possible and recent improvements had been acknowledged by Ofsted.
"However in order to maximise their potential, many students follow courses and work placements in which they gain qualifications which are not necessarily seen as GCSE equivalents, but prepare them appropriately for future employment."
The 2009 results reflected this.
He added: "Unfortunately in February 2009 a consultation for closure was announced and confirmed in July 2009. This was due to the low pupil numbers and excess places in other Chelmsford Schools."
Another Essex school is at the opposite extreme academically. The best A-level performance - for the third year running - was at Colchester Royal Grammar.
Its pupils averaged 1354.7 points. This was slightly less than last year, but still was the equivalent of just over five grade As per head.
Colchester, a selective grammar school, describes the academic achievement of its pupils as its "raison d'etre" and sees exam success as its key performance indicator.
The lowest points attained at A-level - 243.9 - were at George Dixon International School and Sixth Form Centre in Edgbaston, Birmingham, which offers the International Baccalaureate Diploma.
Ofsted notes that it is in a socially, economically and ethnically diverse part of the city, drawing most of its students from areas of severe social deprivation.
An "exceptionally high" proportion of them are newly arrived from overseas.
Overall however the average point score per candidate entered for Level 3 (advanced) qualifications was 739.1 - a slight decrease from 740.0 in 2008.
The GCSE tables also have two measures of pupils' progress, as opposed to the raw results they have achieved.
The first is the contextual value added score, which factors in such things as deprivation and ethnicity.
On this measure, the best performing school in England last year was the Phoenix High School in west London, headed by Sir William Atkinson. It scored 1123.4 on the measure which is centred on 1000.
Ofsted, praising the school, says it "continues to transform the life chances of both students and their families".
The school adding the least value, scoring just 916, was St Peter's in Chelmsford which was also at the bottom of the GCSE results table.
The other type of progress measure, new this year, is based on the principle that children who get the expected national curriculum level when they are aged 11, at the end of primary school, should at least get a grade C when they take their GCSEs five years later.
So schools are rated on the percentage of pupils that do so in English and in maths.
The range is from all pupils (100%) down to just 16% in English, and from 100% to 12% in maths - leading some commentators to say many children are in effect "going backwards".
The tables show that more than half of the pupils in 965 state secondary schools fell behind in either English or mathematics. The Conservatives claimed almost 875,000 pupils were being taught in these schools.
The shadow schools minister, Nick Gibb, called this "very worrying".
Teachers can struggle to keep pupils engaged
"We need more teaching by ability so that gifted children can be stretched and those who require more help can get the specialist attention they need," he said.
The Department for Children, Schools and Families is always keen to promote the achievements of Academies, the independent state schools with external sponsors that are its chief answer to entrenched underachievement.
It said that, for the 63 academies which had been open long enough to have results in both 2008 and 2009, there had been an increase of five percentage points in the number of pupils gaining five A* to C grades at GCSE including English and maths - double the national increase and greater than last year's improvement rate of 4.3 percentage points.
That said, there are 40 Academies among the 300 schools that fall into the "national challenge" scope - those where fewer than 30% of the pupils got give good GCSEs with English and maths, putting them at risk of enforced merger or closure.
Some 54 schools whose results are reported in the 2009 tables have already shut.
Among the 3,027 state schools with valid GCSE results last year and the year before, 1,748 of them (58%) performed better, 252 (8%) stayed the same and 1,027 (34%) had worse results.
The most dramatic improvement, from 41% to 72% (up 31), was at Winchcombe School, a comprehensive in Cheltenham, Gloucestershire.
The biggest fall, from an uncharacteristically high 62% in 2008 to 30% last year (down 32), was at Turves Green Girls' School and Technology College in Northfield, Birmingham.
Each year the DCSF produces a list of "most improved" schools - that is, those that have made the greatest improvement year on year for the past four years.
It is headed this time by the Chafford Hundred Campus Business and Enterprise College in Thurrock, Essex.
Its GCSE attainment has risen from 16% in 2006 to 62% last year, up 46 percentage points - a rise described by Ofsted as "remarkable".
The school is unusual in having pioneered an "integrated curriculum" of life skills "competences" devised by the Royal Society for the encouragement of Arts, Manufactures and Commerce (RSA), but has had to adapt this to fit the requirements of the education system.
Ofsted's last report said: "The school has been tackling a legacy of past underachievement when science teaching was not sufficiently rigorous within the integrated curriculum in these year groups, a concern expressed by some parents.
"Changes to achieve a better balance between thematic teaching across related subjects, and teaching more subjects discretely, including science, are well underway."