Now that's what I call entertainment - every night of every week

ITV's Claudia Rosencrantz refused to accept light TV was a dying genre. She was right, says Ciar Byrne

Think end of the pier. Think magician in a sparkly suit pulling a tired rabbit out of a hat. Then think again. This image of light entertainment is just "such a passé view", insists Claudia Rosencrantz. These days, her channel, ITV, is more likely to show Janet Street-Porter sweating it out in the jungle or Michael Parkinson gently probing an A-list celebrity.

In eight years as ITV's head of entertainment, Rosencrantz has been responsible for some of the most successful television formats of our time, including Pop Idol, Who Wants To Be A Millionaire? and I'm a Celebrity, Get Me Out of Here - which has just entered its fourth series.

For the next fortnight, a sizeable chunk of the television-watching population will tune in at 9pm each night to find out how 10 "celebrities", including Street-Porter, former royal butler Paul Burrell and Vic Reeves' lap-dancing wife, Nancy, fare in the creepy-crawly infested Australian outback.

But with two series in one year, is the successful formula - in April the show averaged more than 11 million viewers - in danger of overexposure? "The last thing on earth that ITV would do is thrash the living daylights out of something," insists Rosencrantz. But the real reason for repeating the show so soon is to fit around the channel's golden boys - Ant and Dec - who also front Saturday Night Takeaway - a reinvention of the "zoo" format pioneered by Noel Edmonds.

Editorially, Rosencrantz is adamant that series four will live up to its predecessors. "I always ring my producers before the ratings come in and say, 'That show was absolutely brilliant, don't worry about the ratings'. Or I will say, 'That didn't work. If the ratings come in tomorrow and it's 15 million, fabulous, but it didn't work editorially'."

Entertainment, let there be no doubt about it, is a serious business, as far as Rosencrantz is concerned. "I'm crystal clear about what my job is and that is to deliver shows that win every slot, every day, every year," she says.

"I don't have the luxury of doing things that I think might be quite fun; that might just be a laugh. This is a job; it's a commercial network." It is a genre she has long championed. When she worked in the US before joining ITV, she asked the major networks why they did not have any entertainment in peak time and refused to accept their verdict when they told her that it was a dying genre.

"Millionaire, the first of my real commissions, not only did the job it did here, it changed networks globally. In America - the very heart of, 'Ooh, entertainment isn't a driver' - there it was driving the peak-time schedule like a juggernaut," she says.

On Saturday nights, Rosencrantz has brought new life to a slot that was perceived to be in decline. This autumn, The X Factor has regularly pulled in 6.5 million viewers, Saturday Night Takeaway 7.5 million and since Parkinson joined the channel with a line up of guests, including Tom Cruise, he has enjoyed an average audience of nearly five million viewers - on a par with his final BBC show.

But she is reluctant to admit there was ever a problem. "There is a popular record that has got a bit stuck that goes round and says, 'Saturday night is in trouble, Saturday night is in trouble'," she says.

"It just isn't true. Volume has reduced over the years as choice of channel has increased - that's obvious. One of the big things that has happened is that Saturday night used to be the only entertainment night when we were kids. Now there is entertainment on every night."

Rosencrantz, 45, has been passionate about entertainment since her days as a researcher with LWT in 1986, before she produced The Dame Edna Experience for 12 years. She had previously worked on Fleet Street as a picture editor and journalist, writing a column for the News of the World. In her spare time, when she isn't watching television, she adores reading - "His Dark Materials by Philip Pullman is one of the greatest books I've ever read" - and spending time with her husband and six-year-old daughter.

Her enthusiasm for the genre extends beyond ITV. She is full of praise for Strictly Come Dancing, which she believes is the first successful entertainment show to come out of the BBC in a long time - "hallelujah, welcome to the hits". She admits that Graham Norton, signed exclusively to the Beeb, is "the only artist that we haven't got on the network that I think is a potential star". But she adds that ITV will only enter into the sort of golden handcuff deals it enjoys with Ant and Dec, Simon Cowell and Parkinson, if they have a definite vehicle in mind.

Despite regular job offers, she is happy to stay put at ITV, and harbours no ambitions to climb up the corporate ladder. She compares her role to that of a chef: "You've got your hob and you've got your dishes; the souffle is about to flop over there and the sprouts are coming to the boil." Post-Blind Date, she has decided to give dating shows a break, and has not recommissioned the weak follow-up, Love on a Saturday Night, with Davina McCall. The achievement Rosencrantz is most pleased about is that ITV entertainment is a "massive deliverer of 16 to 34s [younger viewers] and ABC1s [upmarket viewers]".

She believes the channel has moved upmarket and is simply waiting for public perception to catch up. "It's a bit like Tesco, which used to be thought of as quite a downmarket chain, and actually is an incredibly upmarket one now - it has changed its image so radically."