Even 'Big Brother' is not safe as Channel 4 prepares for a night of the long knives

Mark Thompson, the chief executive of Channel 4, is to mount a root-and-branch clearout of tired and unpopular programmes as he moves to stamp his identity on the 21-year-old station.

RI:SE, the critically lambasted morning show that replaced The Big Breakfast a little over a year ago, is to be axed imminently.

Meanwhile, Fifteen to One, the teatime quiz hosted by William G Stewart, is expected to be dropped after 16 years when its contract with Channel 4 ends next spring. In its place is likely to be a new game show, Beat the Nation, fronted by the station's former chief executive, Michael Grade.

After a year in the job, Thompson is upping the ante. Last week he scrapped both Celebrity Big Brother and Boys and Girls, the late-night youth show that marked the production comeback of Chris Evans. He also put a final end to Brookside, the long-running Merseyside soap that has been dying a lingering death since being relegated to a Saturday daytime slot last year.

Surprise survivors of the swingeing changes are Richard Madeley and Judy Finnigan, who were controversially poached from ITV1 by Thompson's predecessor, Michael Jackson. Their teatime chat show, Richard and Judy, has been re-commissioned for another year, having steadily built up twice the audience their previous show, This Morning, had when they left two years ago.

However, insiders caution against assuming the show will carry on indefinitely. Moreover, while mainstays like Countdown and Channel 4 News are seen as untouchable, there are whispers that even Big Brother might not be safe for ever. After an impressive start, this year's ratings are waning, with the Saturday night average dipping from last year's 4.1 million to 2.7 million.

Thompson's incipient revolution at Channel 4 has been described by one source as "a night of the long knives". Another well-placed source said an announcement was imminent on the future of RI:SE, whose viewing figures have, at times, plunged as low as 50,000. The programme, produced by BSkyB, was given a costly re-launch last Christmas, but its ratings have failed to rise much above 300,000. GMTV, which goes out on ITV1 at the same time, attracts five million.

Referring to RI:SE, the source said: "A decision will be made sooner rather than later." It was also confirmed Fifteen to One faces an uncertain future. "Conversations are going on with Pearson [the show's producer] about whether it will be going forward," they said. "If it does have a future it may be with a different presenter."

Where Thompson's other recent decisions were concerned, however, the source insisted their timing was "coincidental". Though unafraid to axe tired formats without delay, Thompson had felt the need to give other shows, like RI:SE and Boys and Girls, a chance to improve before abandoning them.

"Brookside was a nettle that people feel Michael Jackson should probably have grasped," the source said. "Only in 2002 did ratings really get to the point where it couldn't be avoided, but it had been fading for a long time."

Referring to Boys and Girls, they added: "For us, if a show doesn't get any ratings but gets talked and written about that's often more than enough. If it does neither it's pretty self-evident it's not going to last long."

Last year Thompson cut 100 jobs across Channel 4 and ordered the closure of FilmFour, its movie production arm, in an effort to curb a mounting deficit.

The digital FilmFour channels were re-launched this spring, with the less-watched FilmFour World and FilmFour Extreme replaced by FilmFour Weekly, a new strand which streams the same three films daily at different times over a given week. Channel 4's finances have now stabilised and the revamp has cut losses at its commercial arm, 4 Ventures, to £28m.

Other Doomed Programmes

'Boys and Girls', a Chris Evans-produced game show, was too tacky even for its market. At £500,000 an episode, it cost too much and, more to the point, failed to win viewers.

'Fifteen to One', a cosy teatime quiz, was like 'Weakest Link' without the bitchiness. It now looks doomed.

'RI:SE', gaffe-strewn live morning show fronted by infuriatingly perky identikit 'kidz'. Less 'Big Breakfast' than a dog's dinner, it dies unloved.

'Richard and Judy', the chat show they took to the channel from ITV1. Slowly rebuilding the following they had there.

'Brookside' once had Ricky Tomlinson and Sue Johnston, but silly plots could not help whingeing Scousers compete with moaning EastEnders.