John Lydon thinks Simon Cowell is ''really bad news'' for music.

The Sex Pistols frontman finds the music mogul ''hilarious to watch'' while judging on TV talent shows, but he believes the 'x factor' boss is ''very destructive''.

He said: ''He's really bad news for music. He's hilarious to watch, but he's poisonous, really. He's very destructive and bitter and twisted and evil.''

John has a similar distaste for talent shows, particularly after he turned down 'American Idol' bosses when they asked if a contestant could cover The Sex Pistols' 1977 hit 'Pretty Vacant', because he believes such programmes are ''killing the volatility'' of the music industry.

He added to NME magazine: ''We had a ridiculous situation with 'American Idol', when they wanted to use 'Pretty Vacant' for this contestant, because he was the 'rock singer': the long hair, and the scraggly beard, and the leather jacket.

''No, you cannot use it. Stop it. I don't need someone imitating in that way. You've got the genuine article. What on Earth do you want a fake, phoney version like that for?

''We have the genuine article, but that's not as good as the fake version 10 years later? It kills the volatility - all the great songs in the world make you shiver, and you're going to cover it in marshmallow. Write your own songs, fella, and then I'll judge you.''