I don't know about the accuracy of Gatsos, but before you all assume he is right, bear in mind that the guy who did the research is under threat of a speeding conviction. Therefore, he was probably looking for ways to prove himself innocent. It's also worth bearing in mind the timer he used may have been incorrectly calibrated.
Also, how many Gatsos did he drive past? If he drove past 10 and was flashed by 8 of them, he could conclude 80% are wrong. However, he could drive past another 90, not get caught and suddenly that 80% would become 8%
Interestingly, according to the cornwall police site I link to below, his timings are well within the limits for the camera. The delay between photos is typically anywhere between 500ms and 700ms.
Also, I found an interesting article on how Gatsos work at
http://www.devon-cornwall.police.uk/...tech/gatso.htm OK, I know it's the police, but it does match up with what I read on another site (ukspeedcameras.com) which was selling detectors..