Schools will have to meet tough new GCSE standards to retain specialist status, it was revealed this week.
Sir Cyril Taylor, chairman of the Specialist Schools and Academies Trust, told The TES that secondaries which fail to reach the benchmark by 2008 may be stripped of the extra funding that comes with the status.
The target will be the proportion of pupils getting five Cs or better using the Government's new requirement that the subjects measured include maths and English. It will be set following discussions between the trust and ministers.
The change is intended to ensure schools do not "coast" after being awarded specialist status.
Last year the Government announced that Ofsted would decide whether schools are fit to remain in the programme, which entitles them to around pound;600,000 extra over four years.
Sir Cyril outlined the plans this week as another 123 schools were awarded specialist status. He said: "It is important that we have a series of targets, closely aligned to maths and English, for all schools to meet. Why should schools get extra funding if they are not meeting minimum requirements?
"We don't want this just to become a free-for-all, with everyone becoming a specialist without the need to improve standards."
At the moment, specialist schools must renew their status every four years.
Decisions are based on a series of indicators, including test scores, although they are made on a case-by-case basis. Around 5 per cent of schools fail to regain the status.
It is not yet known how high the new targets will be, although the proposal is likely to alarm some headteachers. The TES revealed last week how more than 100 schools will drop at least 1,000 places in national GCSE league tables as they move from using the old measure of five A* to C GCSEs, to the new one of five A* to Cs, including maths and English.
The tough target for specialist schools is one of two new measures to police them more closely. The education white paper also made it clear that schools graded inadequate by Ofsted would lose their specialist status, but retain the associated funding for a transitional period. They will also be given clear goals to meet before re-applying.
Sir Cyril said tighter checks were needed as England moved closer to achieving specialist status for all secondary schools.
The 123 specialists announced this week - coupled with the 27 independent academies and 11 city technology colleges already established - brings the number to 2,542. The figure is expected to climb to 2,700 when the next round is announced in September. Of the 400 remaining secondary schools, some 150 are expected to be converted into academies.
Sir Cyril said he expected the last 250 schools to apply in 2007 and any remaining secondaries would probably be twinned with high-performing neighbours. "We don't want those remaining schools to be left in never-never land," he said.
The Specialist Schools and Academies Trust also outlined plans to allow high-performing schools - those given the top two ratings by Ofsted - to win additional funding.
Currently, schools can win extra cash by adopting a second subject specialism, taking a specialist role in vocational programmes, becoming a teacher-training school or becoming a partner school, assisting underperforming secondaries.
Sir Cyril revealed plans for two additional funding awards: to schools that give expert tuition to gifted children and to those that assist vulnerable children and children in care.