‘With a small majority, it’s no time

May could regret announcing her support for new grammar schools if she fails to get the measures – which were not part of the last Tory manifesto – through Parliament, the senior minister said. “With such a small majority, now is not the time to be picking a fight like this.”

Sir Patrick McLoughlin, the Tory chairman, has also warned of the dangers of reopening a divisive debate over grammar school education.

Speaking before the new policy was announced, he said it would not “help” to have “a great debate about grammars”.

Rather than focusing on introducing new structures of schools in areas of England where there are no grammars, the Government should raise standards for all pupils in the good comprehensives” told summer.

“Where they have been in operation, they are valued but in areas where they are not in operation, I’m not sure it will help us if we have a great debate as to grammar schools as opposed to no grammar schools,” Sir Patrick warned.

Last night, the Government issued a statement from Sir Patrick insisting that he now supported Mrs May’s new policy “200 per cent”.

The criticism from within the Government underlined the power of the emotive issue of academic selection to split the Tories.

David Cameron suffered his first major rebellion as leader over grammar schools in 2007, when he scrapped the many “very that exist, he earlier this party’s long-standing policy of allowing more selection.

Mrs May reversed that position in a speech on Friday and the Government will spell out more details of the reforms – including extra measures designed to reassure critics – with a Green Paper this week.

The criticism came as Mrs May won enthusiastic backing from two senior MPs – Graham Brady, the chairman of the backbenchers’ 1922 Committee, and John Whittingdale, the former culture secretary.

Writing on these pages, Mr Brady issues a coded rebuke to Tory opponents of the reform, such as Mrs Morgan, who was privately educated but claimed creating new grammars would undermine six years of Tory school reforms. “It is unacceptable in modern