Mossbourne academy in Hackney, east London, is one of eight academies and 13 other state schools operating their own banded admissions systems.
The aim is to ensure they admit pupils across the ability range. Since it opened in 2004 Mossbourne has admitted equal numbers of pupils in four ability ranges.
Sir Michael Wilshaw, the headteacher, said: "If you are going to call yourself a comprehensive, and we are, you have got to have that balance."
First preference is given to pupils with statements of special need - last year there were 11. Then the results of cognitive ability tests taken by all applicants, placing them in one of four bands, come into play. It is only after the academy has ensured it has equal numbers from each band that other criteria - pupils' proximity to the school, for 60 per cent of places, and their distance from another secular, mixed secondary, for the other 40 per cent - are used.
"Banding means you have got a good spread of ability. It means the more able children can help the less able and you are reflecting the nature of the community you serve," said Sir Michael.
Last year Mossbourne had 1,200 applicants for 180 places and Sir Michael warned that banding would not work in under-subscribed schools. But he said it tended to mean a good social mix which benefited the school.
Peter Crook, head of Peckham academy, says his system, which uses five ability bands, means his school has a lower ability profile. "I don't think it benefits the school in any way," he said. "It has been adopted for reasons of transparency and fairness and I would challenge other schools to do the same."
The Bill should make it easier for schools to do so by removing the need for them to publish statutory proposals when making the change.