The Ocado robot swarms that pack your shopping

The first things you notice are the chill in the air, the vast grid on the floor which makes you feel like you're on the film set of the movie Tron, and the whooshing sound of wheels skimming across aluminium. The last thing on your mind is buying groceries. I'm standing upstairs in an Ocado warehouse in Hampshire, England, where grocery orders are assembled and dispatched, watching hundreds of cuboid robots whizz around on a vast metal grid that stretches out as far as I can see. The grocery giant doesn't often let journalists in to its 18 acre (784,080 sq ft) Andover site. With the exception of two or three maintenance engineers on standby, my guide and I are the only humans in the vast space.