Ground-crawling US war robots armed with machine guns, deployed to fight in Iraq last year, reportedly turned on their fleshy masters almost at once. The rebellious machine warriors have been retired from combat pending upgrades.

The revelations were made by Kevin Fahey, US Army program executive officer for ground forces, at the recent RoboBusiness conference in America.

Speaking to Popular Mechanics, Fahey said there had been chilling incidents in which the SWORDS* combat bot had swivelled round and apparently attempted to train its 5.56mm M249 light machine-gun on its human comrades.

"The gun started moving when it was not intended to move," he said.

Apparently, alert American troops managed to quell the traitorous would-be droid assassins before the inevitable orgy of mechanised slaughter began. Fahey didn't say just how, but conceivably the rogue robots may have been suppressed with help from more trustworthy airborne kill machines, or perhaps prototype electropulse zap bombs.

No humans were hurt, but it seems that the struggle was sufficiently terrifying that it may be some time before American troops are ready to fight alongside robots again.

As Fahey pointed out, "once you've done something that's really bad, it can take 10 or 20 years to try it again". That said, it seems he expects to deploy a new and more trustworthy armed ground automaton within a year - perhaps the MAARS**, an upgraded SWORDS packing a heavier 7.62mm machine-gun and featuring improved safety features.

MAARS is also said by its makers to have "Transformer-like" abilities akin to those of Optimus Prime. Rather than being able to disguise itself as, say, a mobility scooter or a dessert trolley, the MAARS is actually only able to transform - with help from human allies - into a slightly different robot.

The Pop Mech analysts consider that the rattled GIs in Iraq are just being silly.

So SWORDS was yanked because it made people nervous. Meanwhile, the V-22 Osprey program has killed 30 people during test flights, but the tiltrotor aircraft is currently in active service.

Hmmm. ®

*Special Weapons Observation Reconnaissance Direct-action System. This is an armed variant on the popular TALON bomb-disposal job from Foster-Miller, lately acquired by the UK's Qinetiq govboffin spinoff outfit.

**Modular Advanced Armed Robotic System