Scientists who have been developing a slug-hunting robot that could be powered by its prey are close to releasing a commercial model. The four-wheeled SlugBot, capable of identifying slugs and capturing them with its extendable arm, has taken several years to perfect. It uses image sensors to distinguish between slugs, snails and worms -- a red light shone on the creatures helps identify the slugs, whose mucus layer shows up brightly in the light. The robot was developed by researchers are the University of the West of England in Bristol, who claim that SlugBot will be able to "live off the land like a predator." Captured slugs will be taken to a base station where they will decompose and release methane gas, which can then be converted to electricity. At the end of Slugbot's 1.8m-long arm is a claw. An electronic sensor attached to the claw uses optical recognition software to spot slugs -- which it appears were chosen as the prey because it is possible to hunt slugs without a Home Office licence. According to the Daily Mail, £200,000 has been spent developing SlugBot. Commercial models could retail for around £1,000. It is estimated that there are as many as 200 slugs in every square meter of winter wheat. An onboard GPS system helps the robot return to base when it has a full crop of slugs or its batteries are low. See the Mobile Technology News Section for full coverage. Have your say instantly, and see what others have said. Click on the TalkBack button and go to the Telecoms forum. Let the editors know what you think in the Mailroom. And read other letters.