The famous street artist and collectors favorite Banksy was charged just a £1 for staging an exhibition in his home town of Bristol on the condition that the CCTV of him putting the display together was destroyed.

A Fredom of Information Act request revealed that the elusive artist, who’s paintings can go for up to £300,000, agreed to the nominal fee from Bristol City Council even though the exhibition at the City Museum and Art Gallery is his biggest ever.

More than 230,000 people has visited the free Banksy Versus Bristol Museum since it opened on June 13 and there are queues snaking for more than 2 miles most days.

The impressive visitor numbers mean the show, which runs until August 31, is on track to become one of the country’s largest exhibitions of 2009. Only six UK exhibitions saw more people through the door during their full runs in 2008.

Bristol City Council deputy leader Simon Cook said: “This is definitely the best pound the city council has ever spent.”

The contract drawn up between the council and a company representing the stencil artist was released online today after a request under the Freedom of Information Act.

It shows the museum agreed to destroy all CCTV footage that might have captured the artist installing, viewing or removing his work, which includes a burnt-out ice cream van and a dummy riot policeman, from the exhibition, 30 days after it was shot.

Key areas of the contract were blacked out, including insurance valuations of each exhibit, clauses relating to the costs of staging the exhibition and the name of the company representing Banksy.

A letter, penned by the council’s legal team, said the sections were hidden as they could lead to the discovery of Banksy’s identity.

“This is because disclosure may lead to the identity of the artist being at risk, which is crucial to his commercial interests and the need to maintain confidentiality regarding the special contractual arrangements between the artist and the council.”

Although the contract does not refer to Banksy or the company which represented him in the agreement, it does refer to an organisation called PCO, understood to refer to Pest Control Office, the official organisation for verifying Banksy works.

Only four people at the museum knew of plans for the Banksy exhibition. The rest of the organisation’s staff were told filming was taking place and that they needed to take several days off work.

Bansky was part of the Bristol underground street art scene before a string of public stunts made him a worldwide figure of intrigue.

At the 2004 Notting Hill Carnival, in London, a wad of £10 notes, that had the Queen’s head replaced by that of Diana, Princess of Wales, were thrown into the crowd.

The same year he smuggled one of his own works into London’s Tate Modern and hung it in the prestigious gallery. He later pulled the same stunt at New York’s Metropolitan Museum of Art.

Banksy has since sold a string of works at auction, including Space Girl & Bird for £288,000, and has been credited with the sharp increase in the popularity of street art.