As the 21st century settles in around us, the influencing machine is quietly making itself at home in the mainstream of our techno-hungry culture. Only a decade ago, the idea of a covert device that uses futuristic technology to send messages and control minds was the hallmark of cults and subcultures: aficionados of the paranoid science fiction of Philip K Dick, or of a samizdat conspiracy literature where mind-control was occasionally proposed as the hidden hand that unifies the disparate narratives of alien abductions and controlling elites.

Now, for every 12-year-old who has seen The X-Files, The Matrix or many other film, TV and comic spin-offs, the influencing machine needs no explanation, and the Internet hums with stories of subliminal messaging, mysterious implants and military mind-control programmes.