The BBC's new digital channel for pre-school children, CBeebies, has become more popular in its first year than the youth channel BBC Choice or the culture network BBC4.
But the sister channel for older children, launched at the same time, has struggled to find an audience and is being reformed to make it more attractive to its target age group.
CBeebies, the new home for programmes such as the Tweenies and Teletubbies, has gained an audience share this year of 6.3% in homes with digital TV, well ahead of its nearest rival Nick Junior. During the summer holidays this year, it is behind only Sky One in homes with digital TV.
CBBC, which is aimed at six- to 13-year-olds, struggles to attract a generation that prefers the diet of US cartoons and action series pumped out by Nickelodeon and the Cartoon Network.
Many children fail to realise that CBBC is a separate channel, because it is also the brand given to children's programming on BBC1 and BBC2.
Nigel Pickard, the BBC's controller of children's programmes, acknowledged there was "a way to go" in establishing CBBC. It launched without enough original material, and tried to appeal to the older end of its target age range.
Mr Pickard was speaking at the launch of a £30m package of children's programming yesterday, headed by Britain's answer to Sabrina the Teenage Witch and a revival of a children's television icon.
Cavegirl features a prehistoric, scantily clad troublesome teenager and her exploits with the "cave boys" - members of her tribe who display a similar disdain for clothing etiquette.
In a development that could concern parents of young children, it emerged that Cavegirl is played by a 20-year-old, Stacey Cadman. In the accompanying magazine, she is described as "petite, slim, stylishly dressed with shimmering blonde hair and a sweet smile".
Mr Pickard denied the programme would contribute to the sexualisation of children, but the show's publicity contains numerous references to the character's allure.
"I think Cavegirl is no problem at all, particularly when you see the whole episodes. It's a lively look at the problems of growing up - the sort of problems that kids have now, but in prehistoric times. It's a bit of fun," he said.
The series is a challenge to US imports such as Sabrina, which have combined sexuality and strength of character in an attempt to appeal to boys and girls.
But if parents are alarmed by Cavegirl, they are likely to be reassured by the return of the differently shaped windows that were a principal attraction of the long defunct children's series Playschool.
Millions were raised on the daily ritual of guessing whether the programme's presenters would take viewers through the round, square or arched windows into a mind-improving film, until the programme ended in 1982.
The feature will form part of a new BBC show, Tikkabilla - taken from the Hindu word for a game similar to hopscotch. Clare Elstow, head of pre-school programmes at the BBC, said the concept of anticipation and prediction played well with children. "It's a classic of its time and if it ain't broke, don't fix it," she said.
· Shows for young minds
Cavegirl
Comedy adventure series starring 20-year-old Stacey Cadman as the "stone age 'sista' who put the pow in girl power". The BBC says that it's a lively look at the problems of growing up as well as good clean fun. But the presence of the caveboys Trunk the Tasty, Stiks the Saucy and Roast the Rugged suggests otherwise.
Fimbles
Intended as a landmark pre-school series, joining the Tweenies and Teletubbies. Fimbo, Florrie and Baby Pom are animal-like characters - played by actors in suits - who live in a magical valley where they make discoveries in each episode.
Tikkabilla
A new magazine show for pre-school children, with music, rhyme and storytelling. The Playschool-style windows will lead viewers into short films, and marks the revival of what became a familiar format for generations of young children.
Ace Lightening
Good versus evil drama series co-produced with the Canadian broadcaster Alliance Atlantis. It caused a stir when a draft report was leaked, suggesting that BBC Worldwide was leaning on CBBC chiefs to secure a prominent slot in the schedules in order to maximise merchandising profits.
The Saturday Show
BBC1's year-old Saturday morning programme has failed to overcome the dominance of SM:tv Live on ITV1. Presenters Dani Behr and Joe Mace have been ditched in favour of faces that will appeal to a younger audience plus a Saturday edition of Top of the Pops, which aims to rival ITV's CD:UK.
