Parents at Bellahouston Academy have enlisted the help of the Commission for Racial Equality over what they claim is a loss of provision for 6,200 pupils whose second language is English. A spokesman for the commission said it was taking legal advice in what could be a UK test case.

The city’s language support service is under pressure following moves to transfer funds from secondary support to the pre-five, primary and special needs sectors where officials say there is evidence of “significant under-achievement” among ethnic minority pupils.

In addition, the secondary support unit for bilingual pupils is likely to be moved from Hillhead High to either Shawlands or Bellahouston academies from next August following consultation.

Willie Hart, local secretary of the Educational Institute of Scotland, said the transfer of funds from the secondary sector would disadvantage pupils and was “regrettable” at a time when the service was still recovering from the removal of 20 posts.

But Hanzala Malik, a vice-chairman of the education committee, gave an assurance that the position in secondary schools would be closely monitored.

These tensions have been given a further twist after the authority decided to back Ian Valentine, the head of Cleveden Secondary, who advertised a post which the EIS believes blurs the long-standing distinction between bilingual support and learning support. Mr Hart said the move amounted to “institutionalised racism”.

Mr Valentine drew protests from teachers of English as a second language (ESL) by advertising for a “teacher of support for bilingual pupils” to fill a bilingual language post. There was no mention of ESL qualifications.

The Cleveden head said the job description was based on the needs of the school. “If there was a change, there was nothing deliberate or sinister about it,” Mr Valentine said. “No one has taken this matter up with me.”

But he confirmed that the successful applicant “could be involved in areas of support other than language”.

Mr Hart said this was a misuse of Government funds that were earmarked for bilingual support. “It is most unfortunate that the education department, which has hitherto been to the fore in supporting the city council’s anti-racist policies, has chosen to go down this road and adopted a position which could be described as a form of institutionalised racism.”

David Smith, an ESL teacher at Shawlands Academy, said a number of his colleagues had written a protest letter to Ken Corsar, the city’s director of education, fearing the Cleveden episode may be the thin end of the wedge.

“If this job goes ahead as advertised, everything is up for grabs,” Mr Smith said. “It means a job can be changed at the whim of a headteacher and this has national as well as local implications.”

Richard Barron, the city’s acting depute director of education, defended its ESL record, pointing out that Glasgow spends pound;200,000 more on teachers for ethnic minorities than allocated by the Government.