The broadcaster, 71, who was sent to Malvern College, Worcestershire, said most private schools were "grubby imitations" of the best, like Eton. And he claimed those, like his parents, who could afford the "extortionate fees", ship their children away to be brought up by strangers.

       Writing for Saga magazine, the former Newsnight host said: "Apart from the lessons given by inspirational teachers, which in some schools is sadly rare, most schooling is a waste of time.

       "In my case, most of my formative years were spent having the rudiments of life dinned into me by a collection of drunks, pederasts and broken men who had returned from the war without escaping its terrors.

       "Somehow the schools are still here. It is not hard to discern why.

       "The best, like Eton, are superb.

       "Their grubby imitations bask in reflected splendour when what they really offer is admission to what is still a recognisable ruling class, with its own tone of voice."

       He added: "Most of us are never going to leave our children any significant wealth ？ perhaps it is enough to give them the knowledge that they are loved.

       "Many people, and my parents were among them, believed that one should also do what one can for their education.

       "Usually, this entailed sending them away to be brought up by strangers."

       Malvern costs more than ￡39,000 a year to attend as a full boarder.