The complete ranked schools's league tables based on GCSE and A-level results 2007

The success of single sex education is evident in the league table of comprehensive schools.

Three of the leading four (and 14 of the top 35) teach only boys or girls up to GCSE level.

Watford Grammar School for Girls in Hertfordshire heads the table. Despite the name, the 300-year-old school has held comprehensive status since 1975.

Helen Hyde, the head teacher, credited the high standards set by staff and their no-nonsense attitude to discipline for the school’s outstanding results.

She said: “It’s the most fantastic school to work in. The staff are exciting and work as a team.”

Mrs Hyde said pupils and staff received training in how to apply different ways of thinking when tackling problems. This is based on Edward de Bono’s ‘Six Thinking Hats’, which advocates looking at issues from various angles, such as positively, negatively, emotionally and creatively.

The 1,250-pupil school, which specialises in maths and visual arts, had an outstanding Ofsted report last September, with top scores in all categories.

It is ethnically and religiously diverse, with Christian, Jewish, Muslim, Sikh and Buddhist pupils, however the intake is very middle class with just one per cent taking free school meals. The national average is 14 per cent.

Mrs Hyde said the school’s ethos was to be warm, friendly and like a family, despite its size. However it is also demanding and challenging for pupils, she said.

“Work comes first and fun afterwards. We don’t allow any nonsense and staff set very high standards for the girls.”

A Catholic boys’ school, The Cardinal Vaughan Memorial School in Kensington, West London, which came joint third in the table, also stresses the importance of firm boundaries and hard work.

Paul Stubbings, the deputy head, said: “The emphasis is very much on old fashioned, traditional values of hard work and self improvement.

“We are aided in this by the Catholic ethos of the school, which unifies staff, parents and pupils, who all pull in the same direction.

“Everyone knows why they’re here and what they’re doing. It builds a sense of momentum, which carries along pupils who wouldn’t do so well at other schools.

“We have a traditional uniform, strict homework timetables and a strong emphasis on discipline, humanely applied. The children thoroughly appreciate it and feel secure because they know exactly what the boundaries are.”

The school specialises in maths and ICT, and also has a strong musical tradition.

It is non selective, racially mixed, has the same number of children on free school meals as the national average, and an above average number of pupils with special educational needs.

Colchester Royal Grammar School in Essex, which teaches only boys, was top of this year’s grammar school league table.

Colyton Grammar School in Devon and Pate’s Grammar School in Cheltenham, came second and third.

However they were among 38 grammar schools which scored 100 per cent in the number of pupils achieving five good GCSEs, including English and maths. Of these, 28 are single sex.

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