By Ray Fleming Cyberwarfare has been a feature of futurist films and sci-fi writing for many years now but it has suddenly become a reality with yesterday's announcement by the Pentagon that the US government is rewriting its military rule book to make cyber-attacks on US computers a possible act of war that could justify retaliatory military strikes.

Only ten days ago the US defence contractor Lockheed Martin made public that it had been the target of “tenacious attacks on its computer systems”. British ministers have also been sounding warnings about cyber-attacks and the Ministry of Defence is said to be recruiting “hundreds of experts” to counter the threat. The example most frequently given of the potential impact of cyber-attacks is of the targetting of the US national electricity grid which could paralyse the whole of the country; a Congressional committee recently produced a report saying that China may already have the capacity to do this.

The Pentagon said that its new rule book will adapt the existing right of self-defence covered by the UN Charter to bring cyber weapons into the category of armed attack. Two questions arise. Whether a single country can make such a definition arbitrarily and whether the source of cyber-attacks can ever be traced with sufficient accuracy to justify a military response.

Answers are not yet available.