Several independent schools taking large numbers of children whose fees are met from public funds have poorer results than their state neighbours.
This week's educational performance tables reveal schools such as St John's College in Southsea, which gets around Pounds 500,000 a year in public money from its 200 assisted places, is outperformed by more than 20 state secondaries in Hampshire.
Other examples include the Friends' School in Saffron Walden, Essex, where 10 state schools achieve a better result than its 68 per cent of 15-year-olds gaining five or more higher-grade GCSEs. The Friends has just over 100 assisted places, bringing in around Pounds 400,000 a year.
The Newport Free grammar, three miles away, also has 66 per cent of its 15-year-olds achieving five higher grade GCSE passes. Saffron Walden County High achieved a GCSE "pass" rate of 63 per cent.
Nineteen of the 355 schools with income from assisted places achieve results below the average for the independent sector of 72.5 per cent of the year group gaining five or more higher grade GCSEs. Exam results of the independent schools on the scheme are on average much higher at 90.1 per cent reaching the GCSE benchmark total.
While all schools on the scheme achieve results above the national average of 44.5 per cent, the worst performers are Worksop College with 27 assisted places and a pass rate for higher-grade GCSEs of 56 per cent and St John's College, Southsea, with 58 per cent.
However, Ronald Forshaw, senior manager at St John's, said the tables distorted the results. Nine Hong Kong students were left out because they were not in the 15-year-old age group. He estimates the score for the school, which has 100 boarders among its 700 pupils, as being in the mid-70s.
The Government plans to double the number of assisted places. The existing 30,000 places cost around Pounds 110 million, but the scheme has just been extended to children as young as five and the Education Bill going through Parliament provides for prep schools to apply.
The Department for Education and Employment estimates the average cost of an assisted place at Pounds 3,800 compared with around Pounds 2,300 in a state secondary school.