There are about 2500 UK independent schools, the majority are junior schools. Over 620,000 children are at independent school, or about 7% of all children in the UK. Regional variations are huge: 4% in Scotland, but 25% in Edinburgh; 13% in London but 10% in the South East. A good fifth of all sixth formers are in independent schools. About half of the parents of these pupils did not themselves attend independent schools.

Official statistics suggest that, at every level of ability, independent school pupils achieve higher GCSE, AS and A-level scores than the total school population (of which they are also a part). Over 50% of GCSE entries from independent schools were awarded a grade A or A*, compared to a national average of 19%; at A level, over 50% were awarded grade A compared to national average of 25%. Independent schools account for well over one third of A-level candidates gaining three grade As or better. Almost all (93%) sixth formers from ISC schools go on to university.