The idea triggered a full-scale revolt on the Google campus. Six years ago, the Silicon Valley giant signed a small, $US14 million contract to put the skills of a few of its most innovative developers to the task of building an artificial intelligence tool that would help the military detect potential targets on the battlefield using drone footage.

Engineers and other Google employees argued that the company should have nothing to do with Project Maven, even if it was designed to help the military discern between civilians and militants.