The decline of the grammar school system is a "tragedy", Boris Johnson said today, making him the latest senior Tory to show his support for academic selection.
The Mayor of London said the schools were a "very important part" of the system and had been "great mobilisers and liberators of people".
His comments came just days after the home secretary Theresa May gave her backing to a new grammar school in her constituency in Maidenhead in Berkshire.
And Kent County Council revived plans today for a new grammar to open in Sevenoaks, despite the proposal being blocked by the former education secretary Michael Gove.
Mr Johnson said he supported the return of the schools, but suggested that changes could be made to alter the "brutal" system of selection at the age of 11.
"I think they are a very important part of the mix in our educational system, I think that they work very well in many areas and they should be supported," he told LBC Radio.
"I think that the decision to get rid of them was a real tragedy for this country."
He added: "Whether you bring back the schools called grammar schools, with academic selection or brutal academic selection at 11, maybe you don't.
"What I think you could do is have a greater degree of academic competition, academic selection at various stages in a child's development.
"There are ways of doing that which wouldn't be hurtful to people, which wouldn't make them feel like failures, but which would spur competition and get better performance out of our schools.
"The principle of academic selection is, I'm afraid, not one that we should jettison.
"There are plenty of fee-paying schools in this country that run absolutely ruthless policies of academic selection."
Ms May's Maidenhead constituency is not in an area that currently has a grammar system and legislation prevents new selective schools from opening. But she has given her backing to a plan to set up a school as a "satellite" of an existing grammar in a neighbouring borough.
She said: "Grammar schools attract considerable support from Maidenhead families. If a good school wishes to expand in line with existing legislation then this must be seriously considered."
Mr Gove previously blocked plans for another satellite grammar school to open in Sevenoaks that would be connected to Weald of Kent grammar school in Tonbridge.
But the council voted through plans for an all-girls school to be opened and planning permission has been granted for a £16-million campus.
Grammar schools opt to give priority to poor children - 1 May 2014
Grammar schools 'widen gap between rich and poor', report claims - 29 May 2014