Something deep in the human psyche seems to lead us to humanise inanimate objects with a personal use, such as boats and cars.

So it is not surprising to learn that some of the 2m people who have bought iRobot Roomba house-cleaning robots over the past five years have become so attached to their little helpers that they have given them affectionate names. Rosie is reported as the most common, after the robotic maid from The Jetsons; other names include Sadi (the cleaning lady) and Marilyn Monrobot. Someone has even set up a business making animal costumes for the device (www.myroombud.com).