Labour and Liberal Democrats MPs have vowed to fight any move to allow new grammar schools in England.

Conservative Neil Carmichael, chairman of the Commons Education Committee, also said he would oppose the move.

It comes after the PM Theresa May was planning to scrap the ban on new grammar schools in a bid to boost "social mobility".

Education Secretary Justine Greening has previously said she is "open minded" on the issue.

Grammar schools are state secondary’s whose pupils are selected by examination at age 10 to 11.

There are currently about 163 in England - out of some 3,000 state secondaries - and a further 69 in Northern Ireland.

But under a law created by the Labour government in 1998, no new grammar schools are allowed to open in England. Education policy is devolved in Scotland, Wales and Northern Ireland.

The Sunday Telegraph quoted an unnamed government source as saying that allowing new grammars would be about "social mobility and making sure that people have the opportunity to capitalise on all of their talents".

Mrs May, who herself attended a grammar school which became a comprehensive school while she was there, is thought to be a supporter of new selective schools.

Responding to the Sunday Telegraph report, Labour's deputy leader Tom Watson said the party would oppose such a move, while shadow education secretary Angela Rayner said selective schools belonged "in the dustbin of history".

Labour leadership contender Owen Smith said grammar schools "entrench disadvantage - they don't overturn it", and promised he would "fight tooth and nail" against any plans to lift the ban.

Lib Dem leader Tim Farron tweeted Lib Dems will work to block any Tory attempt to create grammar schools."

Education select committee chairman Mr Carmichael told BBC Radio 4's Westminster Hour he was opposed to new grammar schools.

"We have serious issues about social mobility, in particular white working-class young people, and I don't think that having more grammar schools is going to help them," he said.

"I think that the creaming off of the best is actually detrimental to the interests of the most."