Former nuclear physicist Stanton Friedman, 71, is one of the world's leading writers and lecturers on UFOs. He has just returned to Canada after his first visit to Hong Kong where he delivered a lecture at the University of Science and Technology titled 'UFOs Are Real'. He explains why he believes in flying saucers even though he has never seen one. I have never seen a flying saucer and I have never seen an alien. But then I have never been to Hong Kong before, but that doesn't mean that before I came I ever doubted that it existed. When I worked as a nuclear physicist I studied many things that I never actually got to see. In the same way, I've never had polio either, but that doesn't mean there is no such thing as polio. I infer the existence of UFOs from sensible observation by other people. It is a subject I have spent decades studying and because of my background as a scientist, people do tend to be more willing to listen to what I have to say and write. My interest in the subject began in 1958 when I read a report on UFOs by a US Air Force captain. I was working on a nuclear propulsion project at the time and I thought it might help our programme. I went to California and found a good library and read 15 more books on the subject. I read a lot of official documents too, and what struck me was that so many reports of flying saucers - 9 per cent in some cases - couldn't be explained away. I was shocked, frankly, by what I discovered. People are still fascinated by the idea of flying saucers and I don't think they are any more sceptical about them today than they were in the 1950s and 1960s. I don't think we are in a more cynical age. There is so much interest in the subject that they run television specials on it at peak times. When I gave a talk in 1968 at one university in a town of 10,000, 2,000 people turned up. It was probably the best-attended lecture they had. I do get a lot of criticism from certain quarters for what I say and write about UFOs. I have to have a thick skin. There are a number of reasons people refuse to believe in the existence of UFOs. One of them is ignorance - they don't read the scientific papers that are out there. Then there is the fear of the unknown. There is also the perception of how others will respond if they say they do believe in them. Another factor is man's ego. If aliens are coming, surely they would want to take his position in the world. We find it hard to accept that the Earth might not be the centre of the universe. Then there is our unwillingness to use our knowledge of technology to understand UFOs. So we are told that it is all baloney. There are certain people who take great pride in their knowledge and take the view that if we are so knowledgeable, we would know about it if it was true. After all, we know about everything that is important, so if we don't know about this, it can't be true. It is a self-fulfilling prophesy. New ideas tend to be accepted not because people come to accept them, but because a new generation comes along. I have had a wonderful reception in Hong Kong and on the mainland, where I attended a UFO conference in Dalian. People came from Taiwan, Australia, Europe, South Africa and from all over. Interest in UFOs in China is enormous. For years, you wouldn't see anything in Chinese newspapers about UFOs. Then it opened up, and today the Chinese UFO organisation is huge. When I'm home in New Brunswick, I relax. My wife has a big family and we have family reunions once a year. In spite of what I do, I don't spend my time scanning the night skies in the hope of one day seeing a UFO. I don't have any great hope or expectation of seeing a flying saucer. I have a different role to play.