Grammar schools should twin with failing comprehensives to improve standards, a government adviser says.
Critics say grammar schools have been "hijacked" by the middle classes
Sir Cyril Taylor, chairman of the Specialist Schools and Academies Trust, said grammars needed to do more to help children from disadvantaged homes.
He told MPs the 164 selective grammar schools in England should form partnerships with weaker local schools.
The comments came as the Conservatives announced they would end their traditional support for grammars.
The party said instead it would back the government's flagship Academies programme which seeks to turn around previously underperforming schools in disadvantaged neighbourhoods.
Speaking to the cross-party Commons Education Select Committee, Sir Cyril said: "The big criticism of grammar schools is that their free school meals eligibility is about 1%, compared to 15-16% for all schools."
But Sir Cyril stopped short of saying grammar schools should be closed: "I'm not in the business of closing highly successful schools."
And he said that parents had the opportunity to decide whether they wanted grammars through local ballots.
There has been a scheme by which the Department for Education and Skills gave some grammar schools money - typically £20,000 each on average - to form partnerships to help other local schools.
Sir Cyril told the MPs the school admissions systems should change so children were not forced to attend unpopular comprehensives.
He backed the use of the "random allocation" of places at popular schools - so-called "lotteries" - for admissions.
He also supported a system known as "fair banding", in which children applying to a school are grouped into different ability "bands".
The school then offers places to even proportions of children from the different bands in an attempt to produce a mixed intake of pupils, from the brightest to those who will struggle.
Sir Cyril said: "I think fair banding and random allocation is the future of the admissions process."
Lotteries and banding are recommended in the government's new school admissions code.
In Brighton and Hove, though, the decision to move to a system of random allocation prompted anger from parents.
Sir Cyril also told the committee that the Specialist Schools and Academies Trust was working to promote the teaching of Mandarin to teenagers.
He said he wanted all 250 specialist language colleges in England to offer Mandarin lessons.
It's a strategic world language," he said.
"But the difficulty is getting teachers that can teach Mandarin. We are hoping to supply that by getting Chinese teachers.
"We now have exchanges between our schools and Chinese schools."
Sir Cyril is a key figure in the government's school policies as an adviser to the Education Secretary, Alan Johnson, who oversees the specialist schools and Academies programmes.