Robot tanks: On patrol but not allowed to shoot

In 1985 the US pulled the plug on a computer-controlled anti-aircraft tank after a series of debacles in which its electronic brain locked guns onto a stand packed with top generals reviewing the device. Mercifully it didn't fire, but did subsequently attack a portable toilet instead of a target drone. The M247 Sergeant York (pictured above) may have been an embarrassing failure, but digital technology and artificial intelligence (AI) have changed the game since then. Today defence contractors around the world are competing to introduce small unmanned tracked vehicles into military service. Just like an army on the move, there are contrasting views about how far and how fast this technology will advance.