James Sabben-Clare, head of Winchester, said: "What we are aiming to do is to provide the best possible all-round education for these selected boys. If you bring together the resources and create the environment then exam success is going to follow. Exam success is incidental to the provision of an all-round education." He said he had seen a dramatic increase in top grades in the past decade and a half and felt exams must be getting easier.
In a highly competitive environment, Winchester beat off old rivals including Eton, which saw its position slide from fourth to eighteenth. Winchester boasted the equivalent of three A grades per pupil - 34.1 points.
A-level results for top independent schools improved sharply this year, according to provisional figures published here, which do not include general studies. The improvement led, once again, to accusations that the exams were getting easier, claims hotly denied by experts within education.
The figures show that 34.8 per cent of independent school A-level entries were awarded grade A, up from 33.5 per cent last year. This is twice the 17.5 per cent recorded for all the schools in the country.
The figures are hardly surprising, given that the schools at the top of the independent school table are highly selective, admitting pupils only by competitive examination. By contrast, most state schools are comprehensive and take pupils of all abilities.
Although the celebrated public schools dominate the top of the Isis table, the full league gives results for 515 schools, with an average of 33.137 candidates: these are mainly local independent day schools, which compete closely at the grass roots with state comprehensive counterparts.
They are by no means all stratospheric performers. Some 212 of the Isis schoolsgained fewer than 20 A-level points per candidate - equivalent to grades of B, C and C.
Winchester, founded in 1382 by William of Wykeham, Bishop of Winchester and chancellor to Richard II, has the longest unbroken history of any school in the country. Alumni include Viscount Whitelaw, Lord Howe and Sir Jeremy Morse, former chairman of Lloyds Bank.
Sevenoaks School is included in the table, although many of its pupils take the International Baccalaureate. Its results are converted to A-level points scores. Hurst Lodge School in Ascot, Berkshire, has been omitted because it had only one entrant, who scored 32 points.