As more and more satellites are sent into orbit from Earth, sightings of Unidentified Flying Objects are also on the up, having risen from 97 in 2006 to 135 in 2007.

Denis Plunkett, of Winterbourne, runs the British Flying Saucer Bureau and says that this number may make up just a fraction of the UFOs in the skies above us, once you take into consideration those sightings that are simply not reported and those that are kept secret by the Ministry of Defence.

"There was an incident in Thornbury recently where a man saw a UFO being pursued by a fighter jet - although the MoD would of course deny this.

"The object was very low to the ground and virtually soundless. The jet, of course, was not!"

The sighting in Thornbury was typical of many of those reported to be seen in the sky in 2007; slow moving, silent craft, often disc- or triangular-shaped, and frequently very low to the ground.

"You find there are hotspots of sightings around the country, and our area is one of them. This may be because we have an easily identifiable North/South, East/West crossing in the form of the motorway interchange, as well as the airfield and a railway bridge."

There is, of course, often a perfectly rational explanation to many of the sightings and Winterbourne is in the flight path of the many extraordinary craft that come in to land at FIlton. But Mr Plunkett insists that there is no way that a flying saucer could be confused with, for example, a hot air balloon.

"These things are massive," he says, "And usually very evasive. I believe that they are primarily sent for surveillance and monitoring purposes.

"Of course it all began after the war, and primarily after the nuclear bombs were set off in Hiroshima and Nagasaki. It has been said that these two explosions could have been witnessed from Mars, so is it any coincidence that the sightings of UFOs began shortly afterwards?"

The British Flying Saucer Bureau was initiated in the autumn of 1952 by Denis Plunkett's late father, Edgar Lawrence Plunkett, and was an off shoot of the international organisation based in Connecticut USA and run by Albert K. Bender.

At that time there were 1,500 members worldwide, but the British branch was left in limbo after three men in black coats' went to visit Mr Bender and the American HQ was disbanded.

Denis took over the organisation in 1993 and has a hardcore of correspondents who still maintain contact and send in reports, although this number is gradually increasing.

"I have a few photographs which clearly show some activity in the sky, such as the ones I have which were taken by a friend at Tortworth Court in 1993.

"He was taking photographs and didn't notice that these objects had appeared until he had the film developed. There's quite clearly something there."

Steven Cotton, general manager of the Four Pillars hotel at Tortworth Court, said: "We haven't seen any unidentified objects. We have the occasional helicopter flying in with guests, but that's all.

"There was, however, a naval training centre here in the 1940s and 50s, so maybe there could be something read into that."