Grammar schools will be given £50 million to expand under new government plans.
Ministers say the cash injection will give parents more choice, with Education Secretary Damian hinds saying that the government wants to “make sure every family can access a good school”.
"By creating new schools where they are needed most and helping all great schools to grow, we can give parents greater choice in looking at schools that are right for their family - and give children of all backgrounds access to a world-class education," he said.
But Geoff Barton, general secretary of the Association of School and College Leaders, said: "We are disappointed that the government has decided to spend scarce funding on expanding grammar schools.
"While there are many good selective schools, just as there are many good non-selective schools, the evidence is clear that expanding the number of selective places is likely to be damaging to social mobility."
If all of the 163 grammar schools in England were given an equal share of the money, they’d receive around £300,000 each.
The ones that want to take on extra pupils will also have to show their plans to admit more children from disadvantaged backgrounds.
Sian Griffiths, education editor at The Times, told Julia Hartley-Brewer this morning that grammar schools are unlikely to improve social mobility unless they change their entrance criteria.
It has been suggested by ministers that grammar schools should lower the pass mark of the entrance test for disadvantaged students.
Hartley-Brewer suggested that if Conservative plans to open more grammar schools had gone ahead, they could have opened in different areas therefore allowing children of all backgrounds to access them.
“I think they would be dominated by the middle classes [even if there were more schools] unless they change their entrance policy and stop having this entrance test at 11,” said Griffiths.
Listen to Sian Griffiths talking to Julia Hartley-Brewer above
“You can’t really get in unless you coach kids through the tests.
“Kids get years of preparation for these tests in middle class families, and only wealthy families can afford to pay the £50 an hour - at least - that it costs.”
The policy is seen by some as a middle ground between the Conservative manifesto at the last election, and the outcry that came from opposers of selective education.
“I think one of the things Theresa May is saying in this policy is that you can open more places at existing grammar schools but you have to take more kids from poorer homes, you have to show you’re taking more children from disadvantaged backgrounds,” said Griffiths.
The plans have been met with derision from education professionals.
Nick Brook, deputy general secretary of the National Association of Head Teachers, said: "The government cannot point to a single piece of evidence that shows strong educational benefit of this misguided policy.
"While it may benefit a small minority, it will not close the gap between rich and poor pupils and if anything will increase the divide.
“School budgets are at breaking point. The state-funded school system is rapidly heading towards insolvency.
To pursue such an elitist policy as expanding grammars at a time of crisis is a distraction at best.
This money should be spent for the benefit of all children, not just the tiny number who attend grammar schools."