Ant and Dec: Pulled in 1.9m viewers

The new programme achieved a 14.7% share of viewing, against its competitor's 35.2%.

SM:tv, which is presented by ex-BBC team Ant and Dec, has out-performed The Saturday Show's predecessor Live & Kicking for some time.

Behr, 26, has said: "We know what we're up against.

"Ant and Dec have been friends for years and their timing is perfect."

But the ex-The Word presenter said she believed The Saturday Show would have "the right content, style and attitude" to challenge ITV1 for the children's audience.

'Long game'

A BBC spokesman told BBC News Online that it was too early to judge how well the show would do.

"We're in it for the long game - this show will be on 52 weeks a year," he said.

"It's a very different show from anything we've put on air before. And it can only build from here."

The first airing of the three-hour Saturday Show featured an appearance from pop singer Sophie Ellis-Bextor plus games including Karaoke Karnage, where stars see their songs "butchered" by audience members.

Meanwhile SM:tv featured a star-studded line-up with Britney Spears, Robbie Williams and Victoria Beckham on the same day.

Past BBC Saturday morning shows

Swap Shop Saturday Superstore Going Live Live & Kicking

Ms Behr made her name presenting Channel 4's notorious late-night youth show The Word, but has appeared in no enduring hits since.

At the launch of The Saturday Show she said that her lack of children's TV work would not be a big problem.

Her co-presenter Mace is a rising star who is so far best-known for his madcap style on Top of the Pops Plus.

The new show features a five-strong house band who were found through a nationwide talent search.

Live & Kicking began in 1993 and was originally hosted by Emma Forbes and Andi Peters, before Zoe Ball and Jamie Theakston replaced them three years later.

But a ratings slide that started when Emma Ledden and Steve Wilson took over, could not be stopped by next and final presenting team Katy Hill, Sarah Cawood, Ortis Deley and Trey Farley.