Science magazine New Scientist reports that boffins have dreamed up a system for herding livestock based on Wi-Fi, GPS, and electric-shock-administering cow-collars. Farmers could one day move herds from one pasture to another using a laptop, as if playing a video game, the publication adds. The system would transmit the GPS co-ordinates of a virtual fence to GPS collars on each animal. Then, if an unfortunate bovine were to stray too close to the invisible boundary, the collar would persuade it to think again. By changing the co-ordinates over time, the herd could be steadily moved in a particular direction. The researchers have demonstrated the system on real cows with static virtual fences, but so far "have only tested the moving version on a group of students". Sneak for one hopes that home secretary and citizen-tracking-fan David Blunkett remains unaware of the story, lest it give him unsuitable ideas.