'Smart' bullets to be a sure-fire hit

They first appeared in cartoons, but "smart bullets" - which follow their target after being fired - may soon become reality.

US military experts have realised that it is possible to build a bullet which can alter its direction during flight by twitching its nose.

The bullets are known as BLAMS - Barrel Launched Adaptive Munitions - and are guided by a laser beam.

Initially the aim is to produce large shells for fighter planes which can follow the twists and turns of an enemy aircraft in a dogfight. But ultimately miniaturisation could make it possible to have hand-held weapons with smart bullets.

Though the individual bullets would be at least five times more expensive than standard ones, they would allow snipers to hit targets several kilometres away with deadly accuracy.

The US Air Force project to build BLAMs has recently been declassified by the US Department of Defense. Ron Barrett, an aerospace engineer at Auburn University, Alabama, told New Scientist magazine: "This technology could change the nature of war."

Each bullet has a swiveling nose that is made to "twitch" by miniature piezoceramic rods, which change length when a voltage is applied to them.

They would be guided by "painting" the target with a laser or microwave beam. Each round would have a sensor that homes in on this signal, just as a smart bomb does.