Art critic Brian Sewell has said that Banksy "should have been put down at birth".

He also said Bristol City Council's proposals to put to the vote what graffiti art in the city should be kept was "bonkers" and that the popularity of Banksy vs Bristol Museum was another sign that "the art world has gone absolutely crazy".

Talking to a national newspaper, Mr Sewell said: "The two words 'graffiti' and 'art' should never be put together.

"The public doesn't know good from bad. For this city to be guided by the opinion of people who don't know anything about art is lunacy. It doesn't matter if they (the public) like it. It will result in a proliferation of entirely random decoration, for want of a better word. Buildings of fine quality, and there are many in Bristol, will be defaced. The architecture must take primacy over whatever street artists may want to do.

"Any fool who can put paint on canvas or turn a cardboard box into a sculpture is lauded.

"Banksy should have been put down at birth. It's no good as art, drawing or painting. His work has no virtue. It's merely the sheer scale of his impudence that has given him so much publicity."

Councillor Gary Hopkins, cabinet member for environment, said: "I think this man needs to get out more. People in Bristol passed comment on whether they liked Banksy four years ago when they voted on keeping his work in Frogmore Street."

Banksy was not available for comment last night.