A Banksy mural worth thousands of pounds has been vandalised rendering it worthless.A stencil image of a monochrome sitting child holding a red balloon which was incorporated into a slogan stating "no future" was discovered recently on a private garden wall in Southampton and resulted in extensive national media coverage. Banksy may have spray painted the mural while on his way to Bestival music festival on the Isle of Wight where he was responsible for providing art work earlier in the year, reported the BBC. The graffiti became popular with local residents and business owners and gallery owner Keith Sekree claimed that it could have been worth up to £35;,000, according to the BBC. Despite its growing popularity, the mural was vandalised by an unidentified person who daubed the image with white paint and added the word "styles" to the end of the phrase "no future". The mural, which was located in the lively Bevois Valley region of Southampton, was identified as a Banksy when it appeared on the street artist's official website but the whitewash has removed any value it once had. Local resident Rose Bowyer told the Metro newspaper that she was upset that the image was attacked because it was authentic art that improved the immediate area surrounding the graffiti. She said: "It is a real shame to see art destroyed so thoughtlessly. The image of the child with a balloon was incredibly potent and how someone can just paint over it like a dirty mark is beyond me." Joe Sidhu, a property developer who owned the house and garden wall, told the Sun newspaper that he was devastated to have lost the Banksy mural but is looking into ways to save it. This is not the first time that work by Banksy has come under attack as rival urban artist King Robbo has been reportedly responsible for changing many of the Bristolian's graffiti around the streets of London. One famous Banksy stencil opposite Archway underground station depicting notorious American Charles Manson as a hitchhiker holding a sign saying "anywhere" was altered to say "going nowhere" and signed "Team Robbo". The dispute allegedly originates from Christmas 2009 when a graffiti artist thought to be Banksy painted over a 25-year-old mural by King Robbo found beneath Camden Street. Meanwhile, an initiative to allow Scottish prisoners the opportunity to recreate Banksy prints with the help of graffiti lessons has been criticised by politicians.