Both are American imports representing totally different philosophies in children's television. One claims a unique empathy with kids - the only word it uses for its audience - as the world's largest producer of original programmes for them. The other consists only of cartoons. Its publicity material proclaims: 'Hey kids, you can watch 14 hours of cartoons a day.' The two channels, Nickelodeon and the Cartoon Network, will be launched in September. Both have enjoyed success as cable channels in the US.
Set up in 1979, as the first channel specifically for children, Nickelodeon is now in 60 million US homes. The Cartoon Network, established only last November, is already in more than five million.
Nickelodeon says it goes much further than the mere business of providing television. It describes itself as the 'kids' advocate', calls its Florida studios the World Headquarters for Kids, and says its mission is to promote the rights and self-esteem of children everywhere.
In April it organised the inaugural meeting of an annual 'Kids World Council', created to allow children to discuss issues that affect their lives. This year's event focused on the environment and was visited by the Vice-President, Al Gore.
'We are 100 per cent for kids,' says Nickelodeon's president, Geraldine Laybourne, one of the channel's founders. 'It is our wish to empower them. Kids should feel part of the world. We did a 'Kids Pick the President' show, and we have a regular news show which helps us get closer to kids' issues.'
Along with this approach, Nickelodeon will be bringing to British children the varied programming that has won it plaudits in the industry. Anna Home, the BBC's head of Children's Programmes, welcomes the new competition. 'Nickelodeon has done some very pioneering things and maintained a mix of game shows, dramas, comedies, animations and factual programmes in a very competitive situation,' she says.
The channel will be on the air between 7am and 9pm. Its launch in the UK is a joint venture between BSkyB and Viacom, Nickelodeon's parent company in the US, which also owns MTV, the music station. It is a major step towards what Viacom calls its 'planetary vision' of a worldwide kids' network.
The Cartoon Network will initially transmit from 5am to 7pm, but according to Sue Kroll, its general manager, it may move to 24 hours a day of non-stop cartoons within two years. She staunchly defends the policy of continuous animation: 'It provides choice. I don't expect children to watch it all day long, but to tune in and out. Cartoons exercise imagination. In the cartoon universe no humans are allowed and rules don't apply. If kids are not watching some cartoons they are missing out on a personal, emotional excursion into a different world.'
The network is based on the apparently never-ending appeal of classic animated favourites. Its highlights will include the Flintstones, Bugs Bunny, Yogi Bear and Scooby Doo, along with more recent creations such as Captain Planet. Part of Turner Broadcasting, it will draw on a vast library of 8,500 cartoons produced under the MGM, Warner Bros and Hanna-Barbera banners.
Both ventures will provide stiff competition for the Children's Channel, the existing service aimed at children. This provides a mix of programming, like Nickelodeon, and is the most popular theme channel on satellite or cable. In homes that have the channel, it accounts for nearly a quarter of viewing by 4 to 13- year-olds in children's broadcast hours.
The Children's Channel is meeting the challenge by developing new programmes for the older age range and increasing audience interaction in its shows. Nick Wilson, programming director, says they involve children extensively in programme research and dismisses as hype Nickelodeon's claims about a unique level of children's participation.
He argues that Nickelodeon could face culture-clash problems due to differences between American and British children. 'British children don't have the same rebellious attitude American children have,' he says. 'We don't make a big thing out of children and adults having some kind of warfare.'
The battle between these channels will commence in September, but more parties may later enter the fray. Children are an important market. One in four already has access to satellite or cable television, and the proportion is steadily growing. The BBC has been considering co-operating with other broadcasters on a new channel to exploit its valuable archives. The competition for children's viewing time is bound to get even more intense.