Street artist Banksy dons disguise to install his picture on gallery wall

Banksy, the street artist best known for daubing buildings and dustbins with graffiti outside the Tate Gallery has had his "art" installed on its walls inside. For a few hours, anyway.

Artwork being considered for display at Tate Britain usually undergoes a rigorous process of nomination. But under heavy disguise, Banksy bypassed the lengthy process by sneaking his work on the wall of Room Seven on the second level when no one was looking.

The artist, who keeps his real name secret in case of prosecution after a career in spray-painting graffiti across London, glued his painting to the wall in a room of 18th-century landscapes as a prank. The "fake" was discovered only when it crashed to the floor hours later.

Banksy visited the Tate, which hosts the Turner Prize on Wednesday, in prosthetic makeup and hat to put up the painting of a rural scene with an image of police tape stencilled on it. A card next to it read: "Banksy 1975. Crimewatch UK Has Ruined The Countryside For All Of Us. 2003. Oil On Canvas."

The caption said Banksy's work is "inspired by cannabis resin and daytime television". The artist had found an unsigned oil painting and stencilled incident tape on it. He says ruining the work in this way reflects how our nation has been vandalised by an obsession with crime and paedophilia.

The caption added: "Any visit to a secluded beauty spot now feels like it may result in being molested or finding discarded body parts. Presented by the artist personally in 2003."

Banksy's agent said: "When people look at the countryside, they think it is an idyllic but you only have to look at what happened in Soham to realise that beneath the surface, it's full of darkness." Many of Banksy's subversive artworks have been acclaimed, including pictures of monkeys with weapons of mass destruction and infants cuddling missiles. Yesterday, the artist was triumphant that his work has featured in the hallowed art establishment. "People often ask whether graffiti is art," he said. "Well, it must be; now it's hanging in the fucking Tate."

A spokesman from Tate Britain said the work was in their lost property. "Whoever owns it can claim it," he said. Banksy is selling another version of the painting, with a video of his prank, for £15,000.