The conclusions of Government inspectors that teaching hours have little association with examination results appears to have been borne out by this year's league tables.
The inclusion of teaching hours in the tables was announced with much fanfare by Prime Minister John Major a year ago, in the midst of a furore over the occasionally massive differences between schools.
Yet an examination of the top comprehensives appears to demonstrate that long hours do not necessarily equal high results. An interim report by the Office for Standards in Education earlier this year found only a very weak association between the amount of taught time and educational achievement measured by tests or examinations.
The Department for Education (DFE) has recommended that secondary-school pupils should have 24 hours of lessons a week, rising to 25 hours for 14- to 16-year-olds - yet the averages for the most successful schools only meet or even fall short of this target.
Old Swinford Hospital in Dudley and Hasmonean in Barnet - ranked third and eleventh - both appear to teach 27 hours a week, but both headteachers believe this may be misleading.
Chris Potter, head of Old Swinford Hospital, said the grant-maintained boarding school teaches a five-half-day week, which he did not think amounted to 27 hours. He thought the figures might have been wrongly extrapolated by the DFE, and attributed the school's success to compulsory, supervised prep that boys do each evening.
At Hasmonean, an Orthodox Jewish school, headteacher Dr Dena Coleman said the 27-hours figure was misleading. That had been recorded in summer when the pupils do a longer week, making up for the winter when school ends at noon on Friday for the start of the Sabbath. Taught hours were closer to 26 but as Hasmonean was a religious school, around a quarter of that was accounted for by RE lessons - bringing "secular" lesson time down to around the average.
Bexley Grammar, the top-ranked comprehensive, teaches a 25-hour week and Bluecoat in Liverpool, came second, with 25.5 hours.
Three of the other top-ranked schools teach an average 24-hour week - indicating that they may fall below Government recommendations for GCSE pupils. Three teach 23.5 hours while one - Hertfordshire and Essex High School, rated sixth - teaches 23 hours.