The most recent legal definition of secondary education in the United Kingdom is contained in the 1996 Education Act. This defines secondary education thus:
full time education suitable to the requirements of pupils of compulsory school age who are either senior pupils or junior pupils of 10 years 6 months and over whom it is expedient to educate with them; and full time education for pupils over compulsory school age but ordinarily under 19, which is suitable for, and provided at, a school.
Mercifully, this is also a fairly apt description of what passes as secondary education in the United Kingdom at the present time. It takes place ...