Schools in England and Wales are becoming more polarised and socially segregated as the drive for more specialist schools continues, an academic has said.

Professor Stephen Gorard of Cardiff University has studied the composition of schools over 13 years and has found that specialist schools are admitting proportionately fewer children from poorer backgrounds.

He says the polarisation in some areas has been more pronounced since 1997.

Professor Gorard says he cannot say there is a direct link between the growth of specialist schools and greater segregation.

I welcome more money for schools but remain deeply disappointed that it should be dispensed in such a discriminatory fashion.

Nigel de Gruchy, NASUWT

"Whether segregation has increased because of specialist schools and diversity of choice in an area, I don't know, but it is happening at the same time," he said.

Specialised schools are allowed to select up to 10% of pupils by aptitude and Professor Gorard says he found segregation most strong when a specialist school was also a church school or a former grant-maintained school (now known as foundation schools).

These schools have more freedom to set their own admissions criteria.

Free school meals

Using free school meals as an indicator of social deprivation, he found that specialist schools were admitting fewer and fewer children from poorer homes.

The effect was not seen in rural areas, where there was just one school and that school took on specialist status - there was no polarisation and the school did reflect its local area.

The research will give fuel to critics of specialist schools who claim that they cream off the brightest or most privileged children and leave the surrounding schools to cater for everyone else.

Teaching unions say specialist schools lead to a two-tier system, with the schools dubbed "bog-standard" by the Prime Minister's spokesman at the bottom.

Resources

Nigel de Gruchy, the general secretary of the National Association of Schoolmasters Union of Women Teachers, said all schools should be given better resources.

"I welcome more money for schools but remain deeply disappointed that it should be dispensed in such a discriminatory fashion," he said.

"Once again, specialist schools are receiving favours over and above that offered to others.

"Where is the level playing field promised by new Labour? What has happened to the Prime Minister's general election mantra of opportunity for all, not just for the few?"

The general secretary of the National Union of Teachers, Doug McAvoy, said the government's policy on specialist schools would do nothing to tackle the core problems facing schools.

"A two tier system, advantaging some schools over others, will simply serve to divide and create disparity of provision for secondary age pupils," he said.

"I cannot see how the creation of more specialist schools can in any way help tackle the vital issues of teacher shortage and teacher morale.

"As partly� selective schools with considerable additional funding it should come as no surprise that specialist schools are able to obtain higher levels of achievement."

Among secondary school heads, there is more support for specialist schools, although this is conditional on every school being given the chance to convert.

Unless all secondary schools have this opportunity, the government risks the creation of a two-tier system.

John Dunford, Secondary Heads Association

John Dunford, the general secretary of the Secondary Heads Association said: "I welcome the large increase in the number of specialist schools and hope that the government will be able to accelerate the programme, so that all secondary schools have the opportunity to gain specialist status within this parliament.

"Unless all secondary schools have this opportunity, the government risks the creation of a two-tier system."

Professor Stephen Gorard believes there should be an attempt to weigh up the costs and benefits of the specialist schools system.

He said: "As with any policy, there will be pros and cons and you have to weigh up the advantages of the specialist schools programme and increase in church schools against the disadvantages this may cause."