THERESA May’s first domestic flagship policy, to create more selective schools as part of her aim to make Britain the “world’s great meritocracy,” has come under strong fire from her own side.

Nicky Morgan, who was sacked by the Prime Minister as Education Secretary in July, has warned her colleague’s big idea to bring back state grammar schools in England – there are none in Scotland and Wales – was "at best a distraction from crucial reforms to raise standards and narrow the attainment gap and at worst risk actively undermining six years of progressive education reform".

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Fellow Tories Neil Carmichael, who chairs the Commons education committee, and Sarah Wollaston, who chairs the Commons health committee, also expressed concerns, underlining the scale of the battle Mrs May faces in getting the radical reforms through Westminster. She has a Commons working majority of just 17.

Also, while Labour pledged to fight the PM’s selective education plans "every step of the way," Liberal Democrat leader Tim Farron predicted the "out-of-date, ineffective approach" would be defeated in the House of Lords, where the Conservative Government does not enjoy a majority.

The plans are particularly vulnerable to a block by peers as they were not included in the 2015 Tory manifesto, thus denying Mrs May power to overrule the second chamber.

Educationalists also expressed opposition, including the Ofsted chief inspector of schools Sir Michael Wilshaw, who accused the Tory leader of trying to "put the clock back" in a way which would halt momentum towards better results in the state system.

During his time in No 10 David Cameron steered clear of the sensitive issue of selective education despite pressure from the right wing of his party. His successor’s early announcement is being seen as a clear attempt to put clear blue water between Mrs May and Mr Cameron in a bid to forge her own distinctive agenda.

The PM believes increasing selective education would boost choice and social mobility of children from poorer backgrounds.

Rejecting critics' claims that the expansion of grammars would consign 11-plus failures to under-achieving "sink schools", she insisted there would be "no return to secondary moderns".

Instead, Mrs May said her reforms were designed to provide "a good school place for every child and one that caters for their individual needs".

She stressed: "This is not a proposal to go back to a binary model of grammars and secondary moderns but to build on our increasingly diverse schools system. It is not a proposal to go back to the 1950s but to look to the future and that future I believe is an exciting one."

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But Mrs Morgan urged the new PM away from creating new and expanding current grammar schools, encouraging her instead to build on the academy and free school reforms pursued under Mr Cameron, which, she argued, were creating "a truly comprehensive school system in which every child is able to achieve excellence".

In her first major policy speech since taking over in Downing Street, Mrs May said the reforms were part of a wider programme to address the "sense of frustration" among struggling voters revealed in the EU referendum. She repeatedly stressed that the changes were intended to help "ordinary working-class families".

"I want Britain to be the world's great meritocracy; a country where everyone has a fair chance to go as far as their talent and their hard work will allow," she said.

"And I want Britain to be a place where advantage is based on merit not privilege; where it is your talent and hard work that matter, not where you were born, who your parents are or what your accent sounds like."

Confirming reforms inadvertently exposed to press photographers in Downing Street, Mrs May announced:

*requirements for grammars to promote social mobility by taking a proportion of pupils from lower-income backgrounds or opening "feeder" primaries in disadvantaged areas;

*lifting the cap on faith schools taking pupils from their own religious community;

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*tougher public benefit tests for independent schools south of the border to retain their charitable status and

*demands on universities in England to sponsor state schools or set up free ones.