There is a very popular play here called Peter Pan wherein Tinkerbell from Fairyland announces she is dying because people don't believe in her any more. The children in the audience then clap like mad and call out, "We believe in fairies, we believe in fairies," and Tinkerbell's light grows bright again and she stops dying forthwith.

If the modern version of Tinkerbell from Fairyland is ET the Extraterrestrial, all the clapping and believing in the world will not keep the little fellow alive. It's official: We don't believe in aliens any more.

The Ministry of Defence Directorate of Intelligence has declared that it no longer wishes to be sent any reports of UFOs (Unidentified Flying Objects) and, perhaps more pertinently, the enthusiasts of the British Flying Saucer Bureau announced they are suspending activities because sightings have dried up. "Perhaps", said a spokesman wanly, "our alien visitors have completed their survey of earth".

These terse announcements tucked away inside a few newspapers in no way reflect the obsessional nature of the events they refer to. For half a century, UFOs were a national fixation, provoking near hysteria in the 1950s and prompting top-secret investigations by the government, a fact that was always denied.

Many of the reports, at a time of Cold War tension with the Soviet Union, were convincing and scary. In 1952, Air Commodore Michael Swinney was an instructor at the RAF Central Flying School. During a Meteor flight with a trainee, he said, "We broke through cloud and I saw three circular white discs in front of me, two on a level keel and one slightly canted. We continued climbing until they took on the aspect of a flat plate."

"I felt we were looking at something we should not be seeing and I was told on landing I looked as if I had seen a ghost."

Swinney's student, Lt. Commander David Croft of the Royal Navy, confirmed the story. "An Air Ministry officer told us the objects had been picked up on radar and had a ground speed of 600 mph. Fighter planes were scrambled but saw nothing.

"I don't know what I saw but I saw something. I don't think there's any way they could have been terrestrial but I have no idea if other beings are around."

In August 1950 at RAF Farnborough, Stan Hubbard, an experienced test pilot, was walking across the airfield when he heard a humming, hissing sound. "I turned round and saw a strange object approaching. It looked like an edge-on view of a sports discus. It was pearly grey and appeared to be crackling and sparking and gave the impression there was something moving on it."

A month later, Hubbard and five other officers had a similar weird sighting from the watch-tower at Farnborough.

The Air Ministry was not convinced and concluded that in the first sighting, Hubbard "was either a victim of an optical illusion or observed some normal aircraft and deceived himself as to its shape and speed." As to the second sighting, the Ministry said, "We conclude that the officers saw some quite normal aircraft at extreme range and were led by the previous report to believe it to be something abnormal, an interesting example of one report inducing another."

"Absolute rubbish," said Hubbard last week. "My engineering experience convinced me it was not of this earth. We do not have the technology capable of that sort of performance."

This was a time when the threat of atomic war with the Soviet Union hung over the world. Whitehall did indeed fear an alien invasion but not from space, from Eastern Europe. In an action it has always denied until records were found recently, the Ministry of Defence in August 1950 set up the 

Flying Saucer Working Party (many UFOs seemed to look like flaying saucers) to sift through the many claimed sightings.

It is clear now why it was all kept secret. For the government to announce that people were seeing things and it did not know what they were would have resulted in a loss of confidence in the armed forces at the peak of the Cold War. And if the UFOs did turn out to be Soviet weapons, to announce they had been seen would reveal the state of Britain's radar and air defences.

So it was mum all round as thousands of reports, often feeding off each other, were meticulously investigated. The Working Party itself was abandoned after just 12 months but military intelligence continued to take an unacknowledged interest in UFO reports for 50 years.

Many of the early sightings were a product of the primitive radar system of the time, experts have since concluded, while others were optical illusions caused by atmospheric conditions.

Researchers believe that if there was a cover-up it was a cover-up of ignorance. Although some things never were explained, official files turned up no trace of a single alien encounter.

Which is rather a pity because I for one would have liked to know more about the experience of an elderly lady from Kensington who said she was visited by a Martian at night. He was seven feet tall and covered in red hair. He said he had been sent to examine her water

Nothing to do with being Scots, I'm sure, but interviews have shown that a lot of city children think eggs come from sheep and potatoes from cows. One boy thought that orange juice came from milk because the milkman delivered his orange juice.

The Royal Highland Education Trust interviewed 126 pupils aged eight and nine in Glasgow, Edinburgh, Aberdeen and Dundee. The survey found that 30 per cent were not sure that eggs came from chickens, 70 per cent thought cotton came from sheep and more than half believed peaches, oranges, lemons and bananas grew in Scotland.

Said study author Jane Methven: "They didn't make the link that we just don't have the sunshine to grow these crops in Scotland."

Some children said they had never been to the rural areas and the Trust is launching a scheme to educate pupils about the countryside. Boys and girls from 50 urban primary schools will visit farms and 600 farmers will be drafted in to tour schools and chat to the kids.

I see we have a new word in the English language, thanks to Nelson Mandela. To cosmonaut and astronaut, he has added Afronaut, for South African space tourist Mark Shuttleworth, the dotcom millionaire who paid £15 million for a trip out of this world and back to Kazakhstan.