Topping the list of furry villains is the Cookie Monster, whose penchant for devouring cookies and the odd plate or two is no longer deemed appropriate behaviour for modern children. His alter ego, Alistair Cookie, host of MonsterPiece Theatre, "modelled the wrong behaviour" by smoking a pipe and eating it, according to Sesame Street producer Carol-Lynn Parente.

Back then, Big Bird's bumbling friend Mr Snuffleupagus was still imaginary, which might encourage "delusion behaviour". And trash-loving Oscar the Grouch has been targetted for his blatant bad manners and questionable hygiene. "We might not be able to create a character like Oscar today," Parente told The New York Times. Like the whitewashing of Enid Blyton books, the move has sparked howls of protest and charges of political correctness sucking the fun out of childhood.

Children's book author Andy Griffiths, creator of the popular "Bum" series, said children loved dark, mischievous characters such as those who lived on Sesame Street. "Kids love seeing their primal desires acted out in the form of things like gluttony or violence, and literature or TV is a place they can safely experience these desires," he said.

"I think it's an entirely healthy and appropriate thing for a children's TV program to be doing." Griffiths said children could tell the difference between fantasy and reality and did not blindly mimic the behaviour of clearly fictional characters. "People who claim to be protecting children always make the assumption that what children see is what they will do," he said. "Underlying that is the assumption that kids can't tell the difference between fantasy and real life and I have found that to be consistently bogus."

Andrew Fuller, a clinical psychologist and consultant on children's television production, said a sanitised world was far more dangerous than the whacky world of Sesame Street. "Unless we expose kids to a diverse range of characters and behaviour they will not be prepared for the real world," he said.

The ABC, which has broadcast Sesame Street since 1971, would no longer consider the original episodes suitable children's material, head of children's programming Tim Brooke-Hunt said. "We might screen them in the context of a discussion about what was happening back then, but now they are not appropriate as children's TV," he said. "The reality is that the majority of kids are not going to copy this behaviour, but as producers of these shows we have to think about what might happen with the minority. "If even a small number of kids might do it you have a problem."

But he admitted such lengths could threaten the joy of childhood. "Yes, I suppose there is that danger, but I just hope parents don't look to TV to give their children all their fun."