Announcement: the Orwellian, Minority Reportian, Matrixian age of the thought police is here.

Remember a time when the biggest risk of using social media was having your boss stumble upon your Facebook photos from the weekend? Those days are long gone and now your online activity could turn you into a convicted criminal.

On 13 January 2010 Paul Chambers answered a knock at his front door to find some stern policemen outside. The first thing he thought was that something terrible had happened to a friend or relative, until they handed him a print out of his Twitter page.

The 26-year-old was arrested under the Terrorism Act and made to endure a seven hour interrogation, following which his laptop, iPhone and home computer were seized. His crime: a Twitter update in which he jokingly threatened to blow up Doncaster’s Robin Hood airport if his flight was delayed due to snow.