Philip Pullman, award-winning author of His Dark Materials, has condemned children's television as "social poison" for treating its audience as a marketing opportunity.

Mr Pullman, from Cumnor, near Oxford, condemned broadcasters for sacrificing high-quality programmes in favour of those that yield more marketing opportunities.

He told a Sunday national newspaper: "Children are regarded by broadcasters as a marketing opportunity at best, a dangerous and feral threat at worst, and an expensive nuisance otherwise.

"This social poison goes much deeper than broadcasting, of course, but it's particularly visible there.

"There used to be ... a sense of responsibility among broadcasters: a feeling that this extraordinary medium ... should be used to make things better, richer, more interesting for those who made up the audience - especially for children."

There are now more than 20 dedicated pay and free-to-air children's channels, but spending on original children's programmes on public service channels has declined in real terms by more than a third, while the average cost of producing one hour of original children's programming fell from £85,000 in 1998 to £57,000 in 2006.

ITV recently announced it would not commission any new children's programmes, a decision that caused Ofcom to launch a review of children's programming, the results of which will be published later this year.

Mr Pullman is concerned the damage done to children's television has gone too far.

He said: "The ideology of 'profit before everything' in children's television is toxic. When young audiences are regarded as customers to be separated from their money as quickly and efficiently as possible, there is no chance for life-enhancing work to flourish."

Some of Mr Pullman's own work has been adapted for television, with the author's blessing.

When Billie Piper and Julie Walters were confirmed as leads for the BBC production of his novel, The Ruby in the Smoke, he said he was delighted, because he had 'always felt that TV, rather than film, was the natural home for the Sally stories'.

New film The Golden Compass, starring Daniel Craig and Nicole Kidman, is the first of three to be based on the His Dark Materials trilogy. It opens on December 7.

The writer is working on a sequel to the trilogy but no date for publication has been set.

The first volume, Northern Lights, won the Carnegie Medal for children s fiction in 1995 and The Amber Spyglass, the last volume, was awarded the Whitbread Book of the Year prize in 2002, the first children's book to win the award.