Grammar schools are being allowed to expand through annexes – which critics claim are new schools – with backing from a £200 million fund.
Opponents warn that the plan to allow existing grammar schools to expand would be bad for social mobility.
But ministers say they will introduce new rules requiring grammar schools to improve access for disadvantaged children.
A new Selective School Expansion Fund will be allocated £50 million for 2018-19, with details of the remaining £150 million to be announced later.
School leaders said they were "disappointed" that the government was spending "scarce funding" on expanding grammars.
Today’s announcement forms part of the government’s long-waited response to its 2016 Schools that Work for Everyone Green Paper consultation.
Theresa May had originally wanted to create a new generation of grammar schools, but was forced to drop the plans after losing her Commons majority in last year’s snap general election.
Today’s announcement also sets out plans for the creation of new faith schools.
Education secretary Damian Hinds said: “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.”
'Damaging social mobility'
School leaders said that the money would be better spent on creating more places in non-selective schools.
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.”
Citing research from the Education Policy Institute, he added that “the evidence is clear that expanding the number of selective places is likely to be damaging to social mobility”.
His views were echoed by Nick Brook, deputy general secretary of the NAHT heads' union, who said: "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.”
Under the government’s plans, grammar schools seeking to expand will have to submit a fair access and partnership plan, including undertakings to give children receiving pupil premium funding a priority in their access arrangements, and a commitment to carry out outreach with primary schools.
A memorandum of understanding between the DfE and the Grammar School Heads’ Association (GSHA) will also outline the sector’s commitment to widen access and work with local schools to raise standards for all children.
GSHA chief executive Jim Skinner said: “We look forward to working with the Department for Education through the memorandum of understanding, to continue and further extend the work that member schools have undertaken in recent years, to increase access for disadvantaged pupils and to support other schools to raise standards for all children.”
However, Melissa Benn, chair of Comprehensive Future, told Tes that grammar schools that have already changed their admissions policies to prioritise children entitled to the pupil premium have only ended up admitting “two or three” additional disadvantaged children.
The creation of new grammar schools was outlawed in 1998, but existing grammar schools are allowed to expand.
'The grammar school corpse' rises again
This includes setting up annexes that can be several miles from the existing school, as long as the new provision is fully integrated with the teaching and learning in the main school.
Last September, the Weald of Kent Grammar School in Tonbridge opened the first such annexe, nine miles away in Sevenoaks.
Ms Benn said it was “hard to say they are not new schools”, and accused the government of “working around Parliament by expanding the schools that exist and saying they are annexes”.
Kevin Courtney, joint general secretary of the NEU teaching union, said: "The grammar school corpse has climbed out of its coffin once again despite evidence of the damage that selective education causes.
"Once prior attainment and pupil background is taken into account, research shows there is no overall attainment impact of grammar schools, either positive or negative."