The Tiffin Girls' School in Kingston upon Thames is at the top of the tree when it comes to GCSE performance among grammar schools.
The girls' school achieved a 100 per cent rate of pupils gaining five or more A*-C/ 9-4 grades at GCSE last year, including English and maths.
It was one of 47 grammar schools in the country to achieve such a success, but the Tiffin Girls' School is set apart by having the highest Progress 8 measure among them.
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There are 164 grammar schools in the Department for Education's data, upon which this table is based.
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While scores of grammar schools managed to get all of their students achieving over five top GCSES, only a handful managed to gain a Progress 8 measure greater than one.
As well as the Tiffin Girls' School, these are Upton Court Grammar School (Slough), Queen Elizabeth's School (Barnet), Nonsuch High School for Girls (Sutton), the Henrietta Barnett School (Barnet) and Kendrick School (Reading).
The Progress 8 measure aims to capture the progress a pupil makes from the end of primary school to the end of key stage 4.
It is calculated for each pupil by comparing their Attainment 8 score (pupils' attainment across eight qualifications) with the average Attainment 8 scores of all pupils nationally who had a similar starting point.
A score of zero means that pupils on average do as well at key stage 4 as other pupils across England who got similar results at the end of key stage 2 - so a positive score means that their progress outpaced that of similar students who used to be at their level.
This year’s GCSE exam results revealed that one fifth - some 20.3 per cent - of entries across all schools nationally achieved an A/7 or higher. 66.6 per cent of entries received a C/4 grade or higher.
This year, changes in GCSE regime meant that a new numerical system was used to mark several subjects.
In an attempt to toughen up GCSEs, the new system uses grades one to nine, rather than from A* to G - with anything above a seven being level to anything above an A in the old system.
Secondary schools have been ranked by the percentage of pupils achieving five or more A*-C/ 9-4 or equivalents including 9-4 in both English and mathematics GCSEs. If schools are tied on this metric, the Progress eight measure is used as a secondary ranking.