A self-feeding ‘gastrobot’ called Chew Chew is to make its debut next month at a robotics conference in Hawaii. The bot is a large 12-wheeled train, with three wheeled wagons each about one metre long housing the robot’s organs.Chew Chew’s stomach is a microbial fuel cell, a device which uses a population of E.coli bacteria to break down food and convert chemical energy into electricity.

At the moment the Chew Chew chews only sugarcubes - these are almost entirely broken down in its stomach, which means Chew-Chew produces almost no robo-faeces. But the ideal diet for the gastrobot is meat, says its inventor, Stuart Wilkinson, which gives a greater energy yield than vegetarian food - so you never know, you might well find a Chew Chew chasing after you in the near future.

The energy Chew Chew’s sugar chewing generates is not currently enough to move the bot directly, so the electricity is used to charge its batteries. When they’re charged the robot can move, and when they are drained, the cycle repeats itself. The idea is to eventually develop robots which are autonomous, according to Wilkinson, who works from the University of South Florida. But if a robot is to be autonomous, he says, the catching of the meat before it is eaten would require a great deal of energy and complex behaviour.

Or, we might add, huge reserves of Sherbert Dip.