Advanced hackers have targeted US and European energy companies in a cyber espionage campaign that has in some cases successfully broken into the core systems that control the companies’ operations, according to researchers at the security firm Symantec.

Having discovered the virus that targetted Iran’s nuclear plants, Liam O’Murchu is one of the world’s top computer security experts, writes Noel Baker. Hacking is now a major industry, and tracking it carries its own risks.