A fan of the 1970s televsion series The Six Million Dollar Man, Spence said he had an epiphany when looking at his mobile phone camera and realising something that small could fit into his empty eye socket. With the camera tucked inside a prosthetic eye, he hopes to be able to record the same things he sees with his working eye, his muscles moving the camera eye just like his real one.

Spence said he planned to become a "human surveillance machine" to explore privacy issues and whether people were "sleepwalking into an Orwellian society". He said his subjects would not know he was filming until afterward but he would have to receive permission from them before including them in his film. His special equipment will consist of a camera, originally designed for colonoscopies, a battery and a wireless transmitter.

It is a challenge to get everything to fit inside the prosthetic eye, but Spence has had help from top engineers, including Steve Mann, who co-founded the wearable computers research group at Massachusetts Institute of Technology in Cambridge, Massachusetts. The camera was provided by California-based OmniVision, a company that specialises in the miniature cameras found in mobile phones, laptops and endoscopes.

Zafer Zamboglu, staff technical product manager at OmniVision, said that success with the eye camera could accelerate research into using the technology to restore vision to blind people. "We believe there's a good future in the prosthetic eye," he said. The team expects to get the camera to work in the next month. Spence, who jokingly calls himself "Eyeborg", told reporters at a media conference in Brussels that the camera hidden in a prosthetic eye - the same pale hazel colour as his real one - would also let him capture more natural conversations than he would with a bulky regular camera.

"As a documentary maker, you're trying to make a connection with a person," he says, "and the best way to make a connection is through eye contact." But Spence also acknowledged privacy concerns.

"The closer I get to putting this camera eye in, the more freaked out people are about me," he said, adding people aren't sure they want to hang around someone who might be filming them at any time." AP