Dr. David Clarke is a journalist, author, university lecturer, and folklorist who is one of the United Kingdom's leading ufologists. Along with Joe McGonagle (#8 on this list), Andy Roberts, and Gary Anthony, he is part of Flying Saucery, and was one of the people responsible for the recent release of the Condign Report, which was the biggest mainstream news ufology has seen since the Peter Jennings documentary "Seeing is Believing".
He teaches journalism at Sheffield Hallam University, and folklore at Sheffield University. He is a regular contributor to BBC History Magazine, and the Fortean Times. His books include Out of the Shadows: UFOs, The Establishment and the Official Cover-up (written with Andy Roberts), The UFOs That Never Were (with Jenny Randles and Andy Roberts), and Phantoms of the Sky: UFOs: A Modern Myth? (with Andy Roberts).
Clarke is definitely a sceptic, much to the chagrin of his critics, most of whom seem to reside on this side of the pond, and most of whom fall into the ETH proponent camp. However, he remains open-minded about the possibility that UFOs might have an exotic origin, although he thinks the most probable explanation is some form of terrestrial, as yet unidentified, atmospheric phenomenon.
Regardless of whether or not you like the cut of Clarke's ufological jib, he is impossible to ignore. He is an intelligent and tenacious researcher as well as a prolific author, and he isn't afraid to speak his mind, no matter whose cage he might rattle in the process.
The serious study of the UFO phenomenon needs more people like him, covering all avenues of discussion, if it is ever to move forward.