The developers of a new prestigious skyscraper project known as London’s Gotham City have secured new protection against thrill-seekers risking their lives to climb the capital’s highest crane. Construction firm Mace is building a 155-metre-high office block in the heart of London’s financial district but the 24-hour security operation is unlikely to deter “urban explorers” from targeting the site, a judge said. "Urbexing" has exploded in the last couple of years and its best-known practitioners attract audiences of millions on social media channels YouTube, TikTok and Facebook. They break into sites to film their precarious exploits on cranes and inside the shells of incomplete buildings. But the craze was said to be responsible for at least 17 deaths around the world from 2013 to 2019, mostly young men in their teens and 20s. One of the latest was Johnny Turner, a free-running enthusiast, who fell from the scaffolding of an eight-storey residential block in 2019. The building project at 40 Leadenhall, with 37 floors above ground, will become the 10th tallest building in the City of London when it is completed in December 2023. The development comprises a series of office blocks near St Paul’s Cathedral with room for around 10,000 workers. Four cranes are on site with the tallest likely to extend to 162.5 metres as construction continues. A judge said on Friday that the £875 million ($1.20bn) office and retail project was likely to be a “tempting challenge” for adventurers in London. Ten other Mace sites across the city were targeted by urban explorers in the nine months up to March 2021, London’s High Court was told. Lawyers for the builder found four examples of online videos of urban explorers operating cranes on construction sites. Photos showed urban explorers involved in dangerous moves, including “performing acrobatic stunts, such as backflips and pull-ups from a crane jib,” judge Mrs Justice Stacey said. “It is self-consciously reckless and risk-taking behaviour.” She said the security measures at Leadenhall were unlikely to be sufficient despite 2.4-metre hoardings, anti-climbing measures, lighting, a system of 20 cameras, electronic tripwires and around-the-clock security. Since 2018, all but one construction site in London involving new buildings of 150 metres or higher has been targeted by urban explorers. The judge highlighted one video of an urban explorer who filmed himself on a building site crane for a video titled, 'Sneaking into the world’s most guarded construction site'. “The site is an attractive trophy site for urban explorers given its size, height, prestige and location, which is very likely to be seen as a tempting challenge,” she said. “The pattern of behaviour and bravado of urban explorers in relation to other notable London sites in the past two years leads me to conclude that the probability of a trespass is not only imminent and real, but also high.” Developers have hit back with court orders targeting repeat climbers. One man was jailed for 26 weeks after breaching court-ordered restrictions. The judge on Friday agreed to a ban on any trespasser climbing higher than five metres at the site.