COUNCILS are spending up to pound;3,000 per pupil maintaining school sixth forms in the face of fierce competition from further education colleges.
The analysis by the NAHT shows that on average councils make annual per capita payments of pound;2,770 per sixth-form pupil, though this represents only about 80 per cent of sixth-form funding.
Government spending plans, meanwhile, show it costs pound;7,380 for a school sixth-former to achieve three A-levels, compared with pound;6,250 at FE colleges and pound;5,910 for sixth-form colleges.
Education Secretary David Blunkett has already guaranteed that sixth-form funding will be safeguarded despite post-16 reforms - but he has said they will be expected to share courses and sites with colleges.
Mr Blunkett has asked why sixth-form colleges produce the same results for less money.
Consultation on sixth-form funding closed last month and decisions are expected soon.
The NAHT says the London borough of Kensington and Chelsea gives its schools the most, at pound;3,316 per sixth-former. Meanest was Bournemouth, at pound;2,008.