The top-selling toy this Christmas is a Gremlin-style creature. But yo-yos are in demand too.
This Year's Top

Ten Toys

1. Furby

2. Yomega X-Brain

3. Pro Yo II and III

4. Beanies

5. C-Watch

6. Talking Teletubbies

7. Scooter Robot

8. Action Man Polar Expedition

9. Baby Born

10. Cool Colours Barbie

Everyone who has the remotest interest in children's toys will have heard of Furby. It is this year's Teletubby - a little gremlin-style creature that talks Furbish (but can be taught English) and has a rather annoying way of telling you that it's bored. "Have you got a Furby in stock?" I asked Hamleys. "You must be joking," came the reply. "They're out as fast as they come in."

It was still the last week of November, weeks before the real Christmas rush kicks off, but the answer was entirely predictable. After all, what would the modern Christmas be without the annual search for the elusive toy that every child wants but only the lucky few can have?

After considerable hunting I found one. Not at pounds 29.99 from Daisy & Tom (they were out of stock) or even pounds 35 from Hamleys, but at Harrods for pounds 39.95. And, even at this not inconsiderable price, the five-inch wonder, created by a Nasa scientist and complete with "microchip" brain, was jumping off the shelves.

While Teletubbies are now piled high (an impossibility last year), Furby is a virtually extinct species: there were only 350,000 available in the UK, and any retailer with a hope of stocking them had already placed orders last January.

Can it really be an accident? "There's no great conspiracy," insists Gerry Masters of the British Association of Toy Retailers. "The prototype Furby was only launched in New York at the toy fair earlier this year and it couldn't go into production until August because they needed to sort out the chips and train staff at several factories. We have a very fashion-conscious market and they just couldn't produce enough."

David Fogel, retail director at Hamleys, couldn't agree more. "We sell 40,000 different lines in Hamleys, but only one will be the mega seller. We were on to Furby straight away and ordered lots. But it is customers that create best-sellers."

But is it? In these days of highly sophisticated marketing, can children's playgrounds fuel annual toy sales of pounds 1.66bn? Yes, there is very definitely some logic to children's fads, believes Judy Harman, planning director at advertising agency J Walter Thompson which works with focus groups of children. She calls it "social glue in the playground". "There are a few core themes motivating children's sales," she says. "Belonging, independence, mastery, simple moral order and bravery and adventure. Enduring brands tap into enduring things, for example Action Man into bravery and adventure."

But computers top most children's wish lists nowadays, which goes a long way towards explaining this year's whole gamut of other hot-selling robotic types. Take C-Watch, the watch with attitude. It may look ordinary but its animated face and sound effects ("you talking to me?") would do the Home Alone hero, Macauley Culkin, credit. Then there's Ziggles, a furry creature with a fat tummy and hysterical giggle (pounds 14.99); or Scooter, the two-foot high radio-controlled robot who can walk, turn and even take peanuts round to guests at grown-up parties. There are even musical lollipop holders, Sound Bites (pounds 7.99), which twirl while you suck.

Build-it-yourself kits have gone techno too. New from K-nex (makers of construction sets such as fairground wheels and dinosaurs) are solar-powered systems, so environmentally aware children can put their batteries to one side and see the wonders of nature. Lego has introduced an "intelligent" brick which you programme and then download by infra-red with its MindStorm Robotics Invention Systems (pounds 160).

Even yo-yos, the essential stocking filler, have clutches, auto returns and ballbearings. Tony Leeming, manager of Harrods' toy department, is used to guiding uninitiated parents through the technological wizardry of the world's one-time simplest toy: "Brains - that's Brain and X Brain - are best for beginners because their centrifugal clutch allows free- spinning and auto returns. It's easy to make them sleep, so there's more time for tricks. The X-Brain with 4 clutches is the most popular. ProYo II (pounds 6.95) and III are the standard, no gimmick yoyos which will sleep but are difficult to master. Then there's the more professional Ballbearings (pounds 99.95)."

Whatever else there is on offer, children will always also like toys which allow their imagination to run free. Playmobil, a great favourite of my own children, has launched System X for the over-fives with a snap grid to hold buildings in place (from pounds 12.99 for a police helicopter); Thomas the Tank has gone remote control (pounds 26); the Wombles are back in town (around pounds 25); and the makers of the Trivia games have come up with the perfect Christmas Day board game, "Who Kidnapped Father Christmas?".

Great for stocking fillers are Roomarangs (pounds 3.99), soft and effective boomerangs which can safely be used inside; Blopens (pounds 4.99), a hybrid of felt-tip and airbrush; and for little girls, Smunchies, soft animals that live in your hair.

And, of course, there are always the perennial favourites like Action Man (this year it is Polar Expedition) and Barbie (this year it is Cool Colours) which are as inevitable as fairy lights on the Christmas tree.

For more information contact: Harrods (0171-730 1234), Hamleys (0171-734 3161) and Daisy & Tom (0171- 352 5000)