Banksy street works to be auctioned in London
A collection of street art by Banksy, removed from walls, has gone on display at a London hotel before the works are sold at auction.
The seven artworks on show include No Ball Games, Liverpool Rat and Girl With Balloon.
Banksy said the exhibition did not have his consent. Auction house Bonhams said buyers should be wary of buying artwork which had not been authenticated.
Organiser Sincura Group said it "sensitively salvages" artwork.
Director Tony Baxter said the company had not gained financially from any sales of Banksy's street work, and that it did not "steal or condone any acts of vandalism or theft".
The practice has attracted critics, with protests being held against the removal and auction of a Slave Labour mural which was on the side of a Poundland store in Wood Green, north London.
In a statement, Mr Baxter said: "The Sincura Group are approached by building owners to remove the artwork illegally painted on their sites.
"The building owners have not asked for the art to be placed on their premises or for the on-going attention received from it.
"What is more, they run the very real risk of having a grade 2 listing applied to their premises which seriously affects their business operations and resale value. Though loved by the public these are often a hindrance to the building owners."
On his website, Banksy said: "The Stealing Banksy exhibition in London has been organised without the involvement of consent of the artist... this show has got nothing to do with me and I think it's disgusting people are allowed to go around displaying art on walls without getting permission."
Ralph Taylor, the director of the UK board of contemporary art at Bonhams, said Sincura was trying to establish a market in selling Banksys and to do that, this exhibition had the aim of generating credibility.
"None of the art work has been authenticated so whether they are sellable is a moot point," he said.
In 2008, Banksy set up Pest Control to verify his artworks, however it only authenticates canvases and prints created by the artist, not his street works.
"People need to know what they are buying," said Mr Taylor, adding: "Bonhams and other auction houses would not entertain the selling of an artwork which doesn't have a certificate of authenticity.
"Street artworks are easy to replicate as people could just download a stencil. Without the signature flourishes of an artist's paint brush it is harder to verify. It just seems to me to be a bit of a brick wall.
"It is up to the living artist to say what is legitimate or not."
The artworks are on display at Me London on the Strand until Sunday. Entry costs £17.50.
The Sincura Group said an auction using online and sealed bids would conclude on Sunday.
In February, the mural Kissing Coppers fetched $575,000 (£345,000) at a US auction after being removed from the wall of a Brighton pub.