British Transport Police arrested four men as part of a crackdown on alleged graffiti artists before the Olympics. Photograph: Lefteris Pitarakis/AP When Adidas wanted to create a mural to illustrate the launch of its new football boot last year, it turned to "professional graffiti artist" Darren Cullen for help. Cullen, 38, runs a firm providing spraycan artwork and branding to major international companies, and says he has never painted illegally on a wall or train. But despite having worked with one of the Games's major sponsors, on Tuesday Cullen was arrested by British Transport Police (BTP) and barred from coming within a mile of any Olympic venue, as part of a pre-emptive sweep against a number of alleged graffiti artists before the Olympics. BTP confirmed that four men from Kent, London and Surrey, aged between 18 and 38, had been arrested on suspicion of conspiracy to commit criminal damage, two of whom were also further arrested on suspicion of incitement to commit criminal damage. They were bailed until November under strict conditions restricting their access to rail, tube and tram transport, preventing them from owning spray paint or marker pens, and ordering them not to go near any Olympic venue in London or elsewhere. None has been charged. The arrests were in connection with "a live and ongoing criminal investigation into linked incidents of criminal damage between January 2007 and July 2012", said a BTP spokesman. But Cullen, who says he has never painted illegally and whose firm Graffiti Kings