The National Union of Teachers has said it is exploring legal action over academy trusts attempting to create new selective schools without new legislation, Schools Week reports.

Government ministers are considering ways to open new grammar schools, without having to repeal the legislative ban on new grammars. Such an attempt to pass the policy through parliament is likely to face opposition, including amongst Conservative backbenchers.

Kevin Courtney, the NUT general secretary, said the union has written to ‘less than half a dozen’ schools which are offering ‘grammar streams’ for pupils who pass an ability test.

Schools such as Swindon Academy place pupils achieving high marks on such tests in a separate cohort, which offers additional opportunities such as Latin lessons.

Courtney said the union was looking to “pick a test case” and try to find grounds for legal action.

He said that in the absence of new legislation to allow the opening of new grammar schools “there shouldn’t be ways of sneaking around [the current ban], and that’s what we think the schools are doing.”

The union is now in contact with schools about their selective processes, although the NUT has not named any institutions specifically.

Clive Romain, the NUT’s senior solicitor, said the union would consider “simple court action” against schools which it believed to be “unlawfully” creating new grammars and so had written to the schools asking for information about how their grammar streams are run.

He said the union would consider other legal options, including a judicial review against any guidance issued by the government encouraging schools to exploit loopholes in admissions laws.

“When parents send their children to what they understand is a comprehensive school and they then learn that in fact there is a particular grammar stream, which is created from a certain group of children who then, throughout their whole school career, are in that privileged grammar stream, with all sorts of perks and benefits, they can be quite understandably concerned about that.”