Poltergeists, virgins and falling crabs: Roger Tredre goes to a birthday party where the guests display encyclopaedic knowledge of some very strange subjects

MY FRIEND Mike used to spend his summer holidays by Loch Ness, looking for the monster. He lived on a diet of fried spam and got very wet, but every summer he would be back, echo-sounder at the ready. Curious really, because when pushed, he would admit that he was virtually convinced the monster did not exist.

But then Mike is a Fortean, one of a small band of people who continue the work of Charles Fort (1874-1932), the American writer who devoted his life to investigating strange phenomena with an open mind. On Monday night, the Forteans gathered at a bar in Notting Hill Gate for a party to mark the 20th anniversary of their magazine, the Fortean Times, published every two months (sales: 20,000 and growing).

It was an event not to be missed. I had always secretly fancied myself as a bit of a Fortean. One of the first stories I had written as a novice reporter was on a BVM in Belgium. A BVM is Fort-speak for an apparition of the Blessed Virgin Mary (other acronyms include SHC - Spontaneous Human Combustion - and the more familiar UFO).

The problem is I have never been prepared to put in the legwork. Forteans all possess encyclopaedic minds, so if you ask them to give you a brief rundown on, say, poltergeists, the chances are you'll be with them until dawn. Last time I went round to dinner with Mike, we spent the entire evening discussing cannibalism. Just as well we ate vegetarian.

In the crowded bar, the Forteans drank with gusto. A surprising number of them wore beards. Mike, who is now a contributing editor to the magazine, gave me a guided tour of the 70 or so guests.

They all had their specialist subjects. John Rowe, a psychology post- graduate, was into crop circles; Yvonne Greene, a part-time astrology lecturer, was interested in UFO abductions; David Norman, a jewellery dealer, couldn't hear enough about the Sasquatch, a huge ape-like creature regularly sighted in North American backwoods.

Yvonne and David had a tale to tell me. 'We had a joint experience,' Yvonne said, 'in a pub in Wembley.'

David saw the look of disbelief on my face. 'It was before we had had a drink,' he insisted. 'The whole pub went into slow-motion, everyone was moving around us in strange, slow, jerky movements. It was very disturbing.'

Even Bob Rickard, the walking library who is the co-editor of Fortean Times, has his fave topic. 'I've always had a soft spot for falling fish,' he said. They fall out of the sky from time to time, apparently, all over the world. It was a remarkably short answer for a Fortean, but then he opened his mouth again. 'And falling crabs, winkles, worms, insect larvae, snakes, toads . . .'

There were dissenters in the room. The editors of Fortean Times have always been good at writing about heavy subjects with a light touch, but some subscribers say the publication has got too populist for its own good - shades of the National Enquirer or the Sunday Sport.

Fort himself might have had his doubts. He would certainly not have approved of Monday night's bash. When invited to be guest of honour at the opening meeting of the first Fortean Society in New York in 1930, he turned it down flat with the memorable words: 'I would sooner be an elk.'