Chinese intellectuals have signed an open letter calling for a boycott of state television news programmes.

The letter says China's Central Television (CCTV) has turned its news and historical drama series into propaganda to brainwash its audience.

The author of the damning letter told the BBC that the action should at least serve as a health warning to the susceptible public.

The authorities have been alarmed by the latest development.

They tend to accuse the Western media of biased coverage of China.

But this open letter accuses CCTV of systematic bias in its news coverage.

'Whitewash'

The letter - signed by more than 20 academics and lawyers - lists six broad categories of bias and brainwashing.

It says the state TV monopoly has ignored many stories of social unrest and riots, and whitewashed serious events like the recent milk contamination scandal.

The letter's author, Ling Cangzhou, told the BBC that its signatories were fed up with the positive spin on domestic news from the central TV station and the negative tone on international events.

He said that the letter should at least alert the public to the problem, though the state TV broadcaster is too pervasive to be boycotted effectively.

Media controls meant the letter had to be published on a US-based website, but it has been picked up widely by Chinese websites.