The Government's determination to increase selection risks wiping out almost a decade of educational achievements, ministers have been warned.
Local authority education directors have told them that selection lowers the expectations of schools, inhibits improvement strategies and reinforces poor performance for children whose achievement is average or below.
The Society of Education Officers, in its response to the White Paper Self-Government for Schools, attacked the drive towards greater selection as ministers prepare to change the rules governing school admission. Legislation this autumn will pave the way for grant-maintained schools to select up to half their pupils and specialist schools to select up to 30 per cent.
Local authority schools will need the agreement of their councils to select up to 20 per cent but governors will be expected to consider at least once a year whether to make their schools more selective.
Using ministers' own watchwords, the SEO urged that "choice and diversity" should be developed as an aspiration for a truly comprehensive system and not a justification for a market-driven system in which schools choose pupils.
It said the major weakness in the British education system since the Second World War had been in the service to average and below-average pupils. And it claimed the largely non-selective pattern of secondary schools working with a national curriculum progressively from 1989 had seen substantial and unprecedented growth in examination performance. "The numbers of average and below-average pupils gaining qualifications has been particularly impressive. "
The society's letter to ministers added: "It makes no sense at all to put those educational gains at risk by encouraging schools to introduce selection and foster the British weakness for admiring only the highest achievements and having low expectations of the rest."
It criticised moves by Government to give grant-maintained schools the power to change their character without external check as "financially irresponsible".
And it warned that allowing the opt-out sector to set up new nursery classes and sixth forms and to expand pupil numbers by 50 per cent would deliberately create surplus places.
Doing this regardless of basic need could have racial implications, it added. "Decisions rejecting proposals for Muslim schools have in the past been rejected on the grounds that there was no basic need for additional school places in that area. This would be of particularly sensitivity in areas where there are existing church grant-maintained schools with mainly white pupils in areas with substantial black or Asian populations."
It welcomed the move to give new powers to the Office for Standards in Education to inspect the work of local authorities but urged safeguards to avoid recrimination and scapegoating.