A media obsessed with quiz shows and soap operas is creating a band of teenagers who know and care little about politics and the world, a head teacher has warned.

Dr Giles Mercer, of Prior Park College in Bath, says the craze for trivia encourages teenagers to gather random facts - but not to develop a real understanding of the world.

He warns a diet of soaps and game shows is contributing to the creation of a "vacuous and unstable society".

He will tell a conference of head teachers of Catholic independent schools on Friday that schools have to work increasingly hard to fill the vacuum.

List mania

"In the media-driven world of popular entertainment, random factual knowledge rather than understanding is at a premium, literally so in the endless game shows," he said.

"List mania rages - top 10s, rich lists, poor lists, what's in, what's out, even a list of the so-called Ten Greatest Britons, none of whom can meaningfully be compared to any of the others and the omissions are laughable.

"These programmes were fine when they started and, in many ways, are harmless in themselves.

"But what is perhaps worrying is how many such programmes have been spawned in recent years and that, together with soaps and other undemanding entertainment, they constitute such a large part of the viewing menu and diet,"

Dr Mercer, who is the chairman of the Catholic Independent Schools' Conference, says the problem is that trivia shows are not balanced by news and political programmes aimed at teenagers.

He said schools had to help young people to make well-informed judgments about the world and to avoid the temptation to fall into passivity or cynicism about politics.