The race to find a successful Saturday morning children's TV show is on - but network bosses are finding it hard to replace Geordie duo Ant and Dec.

Take a few cartoons, a couple of pop acts, some special guests plugging a TV series, a smattering of audience participation, and several cool-looking presenters. A few years ago that would have made a sure-fire Saturday morning TV children's show hit.

Today's young viewers want something different. They have more choice, not just TV with satellite and cable channels dedicated to them, but with computer games and DVDs. They don't need to watch BBC1 or ITV1, the two main suppliers out to woo young viewers at the start of the weekend.

The demise of SM:TV Live illustrates that a format is only as good as its presenters. The trio of Ant, Dec and Cat Deeley helped ITV achieve supremacy over the BBC in the Saturday morning slot for the first time in two decades. Viewers left with them, leaving Auntie to regain the upper hand with the unimaginatively-titled The Saturday Show.

It was only a matter of time before the axe fell, and who better to administer the fatal blow than Nigel Pickard, ITV's new director of programming - the former children's TV head who originally commissioned the series that broke the BBC's monopoly on Saturday morning shows.

Pickard is at the heart of the struggle for young viewers. When he moved to the BBC in 2000, he needed to find a programme to win back viewers as controller of CBBC. He axed Live And Kicking, only to see the replacement, The Saturday Show, struggle.

He was saved by the award-winning Geordie duo moving to adult shows like Pop Idol and their own Ant And Dec's Saturday Night Takeaway.

SM:TV struggled to find presenters as popular as the pair who'd fronted the show for three-and-a half years.

The departure of Deeley was the final straw, although she continues to present companion pop show CD:UK, which will continue until the end of next year.

Where to go from here? ITV needs a fresh outlook. It may look like child's play, but finding the right formula isn't easy. SM:TV Live's demise wasn't announced until a replacement had been lined up. Even then, the currently-untitled new show won't begin until spring 2004.

Rather than a short, sharp death, SM:TV will linger on until the autumn. That will be followed by SM:TV Gold, mixing the best of the live show with clips from the archive.

ITV's controller of children's programmes, Steven Andrew, felt it was time for a change - influenced, we must assume, by SM:TV's ratings decline that has seen it slump from a 48 per cent share to around 15 per cent.

"We have gone for a show that is all about fun with a team with bags of fresh ideas," he says.

The new two-hour show, aimed at a four to 12-year-old audience, hardly sounds ground-breaking with games, sketches, music and acquired programming (which usually translates as American cartoons). The difference is in the increased interactive elements, and there is talk, too, of more location filming.

No news yet either of who'll host the new show, although there have been suggestions that ITV might poach established names from rival CBBC. The search for the new Ant and Dec is on. The pair had early Saturday morning success in Gimme 5, one of several weekend children's shows made by Tyne Tees Television in Newcastle.

Producers have come a cropper in the past. Zoe Ball and Jamie Theakston were a dream team, but Dani Behr proved a nightmare on BBC1's revamped The Saturday Show. She left after posing for a lads' magazine.

Former Hollyoaks actor James Redmond, who hosted SM:TV alongside Big Brother winner Brian Dowling and Tess Daly, admitted to a newspaper that he was embarrassed to be presenting the show and was planning to quit. The producers made it easier by sacking him.

Saturday morning has been a battleground for the BBC and ITV for years. With the content looking pretty much the same, it's been left to the style of the presenters to gain the edge.

ITV had been languishing in second place since the early 1980s when the anarchic Tiswas beat the more traditional Multi-Coloured Swap Shop.

Noel Edmonds, in his pre-Mr Blobby days, wore a cardigan and helped viewers swap items with the help of Maggie Philbin, John Craven and Keith Chegwin.

Tiswas, on the other hand, was often out of control. Chris Tarrant, Lenny Henry, Sally James and Bob Carolgees, not to mention the phantom flan flinger, ensured that the kids had great fun - and quite a few adult viewers, too.

The killjoy at the party was the Independent Broadcasting Authority which frowned on the mayhem and lack of educational value of Tiswas.

The gradual departure of the main presenters ensured its end. The series that followed, Number 73, was odd too - being set in a terraced house in Maidstone, with Sandi Toksvig as the landlady welcoming guests.

Cheggers and Craven hung around to join Mike Read and Sarah Greene in Saturday Superstore, which was Swap Shop by any other name. Then Going Live, with squeaky clean Philip Schofield and Sarah Greene, ensured the BBC kept in front ratings-wise.

ITV struggled with shows like Motormouth, What's Up Doc and Scratchy And Co, as the BBC surged ahead with Live And Kicking with Andi Peters and Emma Forbes, then Zoe and Jamie.

So the battle continues. Finding a successful Saturday show may seem like child's play, but it's not.