In the week after the death of Princess Diana there was another, smaller outbreak of national hysteria. The cause? Teletubby merchandise.

From their arrival in the shops in early September, Teletubby videos and tapes, face masks and playsuits, glitter balls and bubble bath were disappearing from the shelves faster than shopkeepers could restock. Teletubby books were already being reprinted to keep pace with demand; Teletubby soft toys - or “plushes”, costing from Pounds 9 to Pounds 14 - were so sought after that unlicensed models were being pirated (“not tubby enough”, according to a BBC spokeswoman, as well as not conforming to trading safety standards), and were selling well on street stalls. Only last week I heard of a birthday party that was wrecked by six-year-olds fighting over these toys.

But when, with considerable difficulty, I managed to obtain from the BBC two Teletubbies videos, two books and one tape, I could not help wondering what all the fuss was about. With two young children of my own, I am no stranger to Teletubbies, and my three-year-old enjoys the programme. But I would not pay Pounds 9.99 for a video called Here Come the Teletubbies, which includes so many elements from the daily programme that you would be much better off simply recording an episode or two for yourself. Dance with the Teletubbies, also Pounds 9.99, has the famous four stamping and stepping, walking and running away, and taking it in turns (good educational idea, that) to wear a tutu. An inset for parents informs us that the video will help develop children’s sense of rhythm, which is “very important in developing very early reading skills”.

But how many children really need Teletubbies videos to be able to respond to music in this way?

Fun with the Teletubbies, the tape, at Pounds 2.99, is made up of a medley of spoken rhyme, snippets of song, sound effects and the controversial Teletubby-speak (plenty of “tustard” and “piders”), which I found confusing. Most disappointing of all (though cheap at Pounds 2.50) are the books, with their innocuous texts and oddly pallid pictures. My three-year-old has shown no desire to re-read these.

Confronted with a large display of such products at her local Mothercare, one mother of a two-year-old said she found them “unappealing and insipid”, and much inferior in quality of design and story-telling to merchandise derived from popular book characters such as Thomas the Tank Engine. Another mother of a three-year-old said she could not find anything attractive about Teletubbies, and hated the attendant commercialism - although she conceded that she might buy a Teletubby product rather than something more violent, like Power Rangers.

But how many parents will be able to resist the pressure to buy Teletubbies paraphernalia in the run-up to Christmas? A BBC spokeswoman said the corporation was aware of the commercial pressures on parents, and was trying to keep some prices down. The BBC also denies flooding the market in the pre-Christmas period. (It does, however, have a three-year plan for the slow release of Teletubby goods, including clothes and shoes, with marketing campaigns planned for next year.) The corporation points out that it has refused licences, which it would not have done had profiteering been its sole objective.

Programmes for older children, often imported from the US, such as the Teenage Mutant Ninja Turtles, have generated similar buying frenzies, only to die out after a year or so; who now remembers anything about Donatello, Michelangelo and the rest?

But Teletubbies is the first programme for pre-school children to have aroused interest on this scale, a phenomenon undoubtedly helped by the media debate about whether Teletubby-speak helps or interferes with young children’s language development.

Playdays, which began 10 years ago, is, in my view, a far richer and more varied programme for this age group (and preferred by my own children to Teletubbies), but the shops aren’t spilling over with Why Birds and Peggy Patches. So what is so special about Teletubbies?

Part of the answer, according to the BBC, lies in the growing sophistication of the market. “Children now expect to have these sorts of products linked to their favourite programmes, and it would be unkind not to provide them, ” says a spokeswoman.

The Teletubbies also lend themselves particularly well to mass merchandising, being brightly coloured, easily identifiable and just the sort of cuddly image to have stamped on your hot water bottle, sock, or lunch box.

So will parents still be buying Teletubby plushes next Christmas? Does the show really have the depth to sustain the long-term interest of, say, a Beatrix Potter character, or a Paddington Bear?

Parents may have their doubts, but the BBC is confident that sales of Teletubby goods will hold up for as long as the programme retains its daily half-hour slot, which could be for up to five years. “It won’t stop, because the children love it,” is the official line.