PUPILS should not be admitted to grammar school simply on the basis of passing a selection test, MPs have warned.
A report by the cross-party education select committee at Westminster said ministers in Britain have not yet shown how a selective system could be set up that would not be "gamed" by families who can afford to pay for tutors.
It also said the government must demonstrate that creating a new wave of grammars will help close the achievement gap between rich and poor children.
Plans to expand selective state school education were unveiled by Prime Minister Theresa May last autumn.
Mrs May has argued that grammars can help the life chances of poorer pupils, and that the existing largely comprehensive system sees "selection by stealth" based on parents' wealth and ability to buy houses near the best schools.
Opponents argue that expansion will lead to segregation and a two-tier education system.
Children are awarded places to grammar schools based on academic ability - typically through their performance on a test such as the 11-plus.
In Northern Ireland, most grammar schools continue to operate their own unregulated entrance exams.
Education minister Peter Weir of the DUP has said he would consider ways to make the use of selection easier for pupils, parents and schools.
Unions, however, say supporting academic selection in the north's schools would create a social and economic vacuum.
In a new report, the select committee said it was told by British schools minister Nick Gibb that creating a tutor-proof entrance test for grammar schools was a "holy grail".
If this was the case, the MPs concluded that selection tests "should not be the only basis on which admissions to grammar schools are based".
"The government has yet to demonstrate how an admissions system could be designed in a manner which would be immune to gaming, or being reduced to the ability to pay," the report said.
"The government must demonstrate how the creation of new grammar schools will help close the attainment gap within the wider school system, not just for individual pupils."
Committee chairman Neil Carmichael said the government was yet to prove the case for opening a new wave of grammar schools.
"If the government wants to push ahead with new grammar schools it must demonstrate how this aids social mobility and improves educational outcomes for all, most especially those from disadvantaged backgrounds," the Conservative MP said.
"The focus on opening new grammar schools is, in my view, an unnecessary distraction from the need to ensure all our young people are equipped with the skills to compete in the modern workplace."
