As Stephen Hawking once put it: "The physics that underlies Star Trek is surely worth investigating." Which should lift the spirits of police chief Ian Arundale, who was mocked at the weekend when he said he wanted such a weapon for his officers.
"What we would like in the future is a Star Trek-style phaser that, perfectly safely, temporarily switches someone's brain off so that officers move in," Arundale, assistant chief constable of West Mercia police and the head of the Association of Chief Police Officers' use of firearms unit, told Jane's Police Review magazine.
Scientists say in principle such a weapon might be possible, but that you'd never get it through the door. "You need extremely high voltages and so it would be something the size of a car," says Karl Krushelnick, head of the plasma physics group at Imperial College London.
In 1997 Eric Herr of Californian company HSV Technologies patented a design using laser light. The lasers generate intense beams of ultraviolet light that create a path of ionised air between the weapon and the target, up to 100m away. The air then conducts an electric current to cause muscle spasms or stun for a few seconds. Herr says he is developing a prototype device about the size of a suitcase.