David Cameron slaps down Boris Johnson over IQ row

“I think it is very important that we do everything to say that we maximise people's opportunities to make the most of their talents. I believed in equality of opportunity."

Mr Cameron, who like Mr Johnson went to Eton, added: “No one should be held back by not being able to get the training, the education, the skills that they need.

“Everyone has their own way of putting these things and I will leave Boris to talk for Boris.”

On Sunday Mr Osborne said that he didn't “agree with everything” Mr Johnson said.

Mr Osborne added that there was “increasing agreement” that it is impossible to achieve “equality of outcome, but you should be able to achieve equality of opportunity wherever you come from.”

The Chancellor told the BBC’s Andrew Marr Show: “I wouldn’t have put it like that, I don’t agree with everything he said.

“What I think there is actually increasingly common agreement, across the political spectrum is that you can’t achieve equality of outcome, but you should be able to achieve equality of opportunity wherever you come from, the best chance, and actually education is the absolutely key to this.”

Mr Johnson, who is considered to be a Conservative leadership rival to Mr Cameron, had also said that IQ should be part of the conversation about equality leading critics to describe his views as “unpleasant, careless elitism.”

Ed Balls, Mr Osborne’s Labour shadow, said that Mr Johnson’s suggestion that grammar schools should be revived to enable the brightest “cornflakes” to rise to the top of the packet was an “outdated” view of society.