Rise of the killer robots: Experts reveal just how close we are to a Terminator-style takeover

It's been exactly 40 years since The Terminator hit the big screen, shocking cinemagoers with its terrifying depiction of a post-apocalyptic future. In James Cameron's epic sci-fi blockbuster, billions of people are killed when self-aware machines trigger a global nuclear war around the start of the 21st century. Arnold Schwarzenegger stars as the eponymous robotic assassin sent back in time from 2029 to 1984 to eliminate the threat of a human resistance. Famously, the Terminator, which looks just like an adult human, 'absolutely will not stop … until you are dead', as one character puts it. While this sounds like pure sci-fi, academic and industry figures – including Elon Musk – fear that humanity will indeed be annihilated by AI. But when exactly will this happen?