School league tables of exam results are published by newspapers.
The UK government also publishes Performance Tables on the Department of Education website.
Many of the best independent schools enter pupils for the International GCSE in some subjects when the pupils are 16. The iGCSE does not appear in the DFE Performance Tables and this is why such table can list our highest-achieving schools as having scored zero passes in English and Mathematics. That is why the A-level grade score is a better statistic to use when comparing schools.