"How not to build the Terminator" - two disturbing days at the 'world cup' for robots

What really happens at the US Defence Agency's annual robotics showdown, and what are Uber, Amazon and Elon Musk doing in the crowd?

" Humanoid robots - in pictures

It's surprisingly transfixing watching robots - great, lumbering, 7ft-tall humanoids - trying to walk and use power tools and drive a car. But it's not the only spectator sport on hand at the Darpa Robotic Challenge. There's also spot-the-billionaire. The first one I clock is Larry Page, co-founder of Google, who walks right in front of me leading his young son by the hand. "Larry!" I say, but then hesitate. I'm not sure how this question will end. "Is Google planning to build a race of superbots that will take over the earth?" is perhaps too bold an opener. "Could I just " ?" I say but he simply smiles and walks away.

Given that Google bought multiple AI and robotics companies 18 months ago on a secret shopping spree, including a Japanese one, Schaft, which won the first round of the Darpa challenge, it's hardly surprising that Page has turned up for what is the World Cup of cutting edge robotics. Or what Gill Pratt, the programme director at Darpa who designed the competition, calls "the Super Bowl for nerds". Because what Google is planning to do with its robots is one of the many hot topics of the weekend. The company has "gone dark", Will Knight of MIT Tech Review says. "Nobody knows. It's a complete mystery. Though it's also possible that even Google doesn't know what to do with them yet."