Banksy street art pieces that have been removed from their original locations are to be auctioned off in London, the BBC reports. The artworks include No Ball Games, Old Skool, and Sperm Alarm, and are expected to fetch hundreds of thousands of pounds.

The sale will take place on April 27. It is organized by Stealing Banksy?, a controversial project by the art branch of the luxury concierge Sincura Group. “The Sincura Group do not steal art nor do we condone any acts of wanted vandalism or theft,” said director Tony Baxter in a statement. “We do not own the pieces of art, have never approached anyone to remove any artwork, or encourage its removal.”

He goes on to explain they “sensitively salvage” Banksy only when approached by landlords, and are yet to make a profit from the initiative. “The building owners have not asked for the art to be placed on their premises or for the ongoing attention received from it. What’s 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.”

Unlike Banksy’s paintings and prints, the street art pieces are not certified by the artist’s Pest Control. “Street artworks are easy to replicate as people could just download a stencil,” Ralph Taylor, the director of the UK board of contemporary art at Bonhams told the BBC. “Without the signature flourishes of an artist’s paint brush [authenticity] is harder to verify.”

The artworks are shown in a fee-paying exhibition at the Me London hotel until Sunday.