Ho Ho Eh-Ho, everyone

The Teletubbies

Born: March 1997; to the BBC children's programme department and Ragdoll productions

Names: Tinky-winky, Dipsy, Laa-Laa, Po.

Where they live: Teletubbyland; a rabbit-intensive community of grassy knolls.

Also, the tubbytronic superdome, which contains the tubbies' sleeping quarters and the high-tech equipment that produces their life-sustaining tubby toast and tubby custard. The superdome is also home to the Noo-noo, an eccentric vacuum cleaner (but aren't they all!) gobbling up the custard spillages and toast-related accidents that are a constant but always thrilling feature of the tubbies' lives. Sometimes the Noo-noo goes a bit mad and chases the Teletubbies around the room.

What they do: Live happily together in a fantasy world, acting out the highly complex plots devised by the script-writers, a typical example of which would be: "LaaLaa finds a hat!" Not all the plots are as complicated as this. The tubbies also have built-in aerials and TV screens which pick up transmissions from a windmill - don't even ask - and broadcast films of children's activity from the real world. They always demand to see each video twice, shouting "Again! Again!" excitedly, no matter how boring it was the first time. Their tenuous grip on reality is reinforced by voice trumpets through which they receive orders and suggestions from the outside world, a process with uncanny similarities to the adult TV hit, Big Brother.

Idiosyncracies: Tinky Winky is purple and, as well as singing the Tinky Winky song, likes to dance and fall over on his back. Dipsy is green and the "coolest" of the Teletubbies, a status he somehow combines with having a special song that goes "Bup-a-tum, Bup-a-tum, Bup-a-tum." Laa-Laa - yellow - is the happiest and, in the face of stiff competition, the silliest of the Teletubbies. Po is red and likes to jump up and down.

Bear in the Big Blue House

Born: 1997, in the Jim Henson muppet stable

Who he is: A house-trained bear who combines a highly humane personality with such authentic bear habits as scratching himself and sniffing: a combination which makes him a hero to adult male viewers. He begins each programme, in fact, by opening his front door and noticing a smell, whereupon he pushes his nose up to the camera lens, and announces that it belongs to the viewer. This can be disconcerting early in the morning, but the tension is always defused when the bear assures us the smell is a good smell, like "butter cookies" or "new mown hay".

What he does: Shares his home with a menagerie of little friends, and casts light on their frequently confused activities. They include Tutter, a highly excitable blue mouse who combines large-animal ambitions with tiny-animal levels of ability; Treelo, a highly excitable lemur with communication difficulties; Pip and Pop, highly excitable twin otters; and Ojo, a highly excitable small bear (no relation).

The point of all this: In a patient and always non-judgmental way, the bear applies trusted problem-solving techniques to the small animals' difficulties, in the process teaching what the programme producers call a "real-world curriculum" to pre-school viewers. Lessons are sometimes accompanied by music and dance. No one who saw Bear sing "Everybody's gotta poop sometime" in the classic episode Potty Time with Bear would ever again indulge in wild generalisations about what bears do in the woods.

Idiosyncracies: With so many highly excitable small animals running all over the house, a bear could go mad. But he keeps his sanity by talking to the moon. His other friend, "Shadow," is an example of the global scourge that is Riverdance. Although her nationality is never specified, Shadow is a young woman with a pony-tail and an Irish accent whose shape appears on the bear's walls accompanied by a burst of fiddle music, and who says Rose of Tralee-type things like: "Get way outta that ye big old bear!"

Barney

Born: In a traffic jam in Dallas during the mid-1980s. Sheryl Leach was frustrated at the lack of TV shows that engaged the attention of her two-year-old, and filmed the first Barney videos in her father's studio in 1987. Since 1992, when PBS broadcast it across America, the show has earned international fame with small children, and the hatred of millions of parents.

What he is: According to the producers, "an incredibly lovable, warm and friendly six-foot purple dinosaur". Most adults agree only about the six-foot purple dinosaur part. However, he does undoubtedly have a mesmerising effect on impressionable youth, leading one American humorist to suggest the dinosaur costume could be a disguise for L Ron Hubbard.

What he does: Have fun and games with a group of school children carefully selected to represent all the major ethnic, religious and body-size groups in the US. Some of the children are suspected of having had personality-enhancement surgery, but no allegations have been proved. Barney's three favourite words are "fun", "fun" and "fun"; but the fun always involves a lesson in good American citizenship: whether it's the need to conserve water or the importance of pushing that chad all the way through when voting for president. A typical Barney song goes: "When I'm brushing my teeth and having so much fun/I never let the water run - no!/I never let the water run."

Strange but true fact: The show's creator originally thought of making Barney an animated comfort blanket rather than a dinosaur!

Postman Pat

Born: In the Northumberland village of Wooler during the 1950s, where his creator John Cunliffe worked in a mobile library. Adapted for BBC television in 1981.

Who he is: Real name Pat Clifton, a hardworking postman who drives his red mail-van around the incredibly narrow, winding roads of Greendale where, luckily, he never meets a car coming in the opposite direction. Greendale is an idyllic village in the hills where you'd expect that nothing ever happens. But you'd be wrong, because Pat finds many adventures on his rounds, a fact which explains one of his favourite expressions: "What a strange day!"

Why it's popular with children: In common with other pre-school heroes, like Barney and the Bear, Pat is a problem solver. When things go wrong in Glendale, and they often do, despite the village society's porridge-like stability, Pat can be relied upon to sort things out. A self-effacing paragon of virtue (notwithstanding the fact that his mail-van has a vanity number-plate "PAT 1") he is a mobile comfort blanket for his whole community.

Typical plot: Greendale is enveloped with thick snow, rendering the mountain roads impassable, but the post office has an urgent package for George at Hilltop Farm. Postman Pat is undaunted, delivering the parcel along with emergency food supplies and a bale of hay for some stricken sheep, by sled. Along the way, he helps dig out a stranded snow-plough, delivers the parish magazine for the rector who has broken his leg on the ice, and somehow finds time for a vigorous but good-natured snowball fight with local children.

Sesame Street

Born: 1969, to the Children's Television Workshop in the US. Jim Henson created the accompanying muppets (and more than three decades on, the Henson company is currently working on The Hoobs, a major series for Channel 4 aimed at the first generation of multi-media pre-schoolers!)

What it is: Originally aimed at pre-school children in America's inner cities, the show reached a much wider audience thanks to the popularity of the muppets among the commercially important five84 age group. Characters such as Kermit the Frog, Bert and Ernie, the Cookie Monster and Big Bird took on a life of their own (Kermit had been around since 1955, in fact), spawning the Muppet Show in 1976.

Serious educational element: Sesame Street teaches children how to read, count, observe and "be a friend". Individual numbers are featured on the show like A-list celebrities, and the series was for many years sponsored by non-profit making letters of the alphabet, for example "M," each of which would received extensive publicity during the course of the programme.

Sour note: The letter-sponsorship ended when the show signed a $1 million commercial deal with Discovery Zone in 1998. That move was condemned by consumer advocate and presidential candidate Ralph Nader, who suggested the series be renamed Huckster Alley.