Fame Academy ratings are currently modest

Peter Bazalgette, who brought Big Brother to the UK, wrote in the Evening Standard that channels should focus on carefully targeted shows.

He told the paper that Saturday evening TV had changed from the most popular night to the least popular.

"No programme will again attract a regular audience of 12 million on a Saturday," the chairman of Endemol said.

In the past, BBC and ITV used to enjoy bumper ratings for family shows such as The Generation Game and Blind Date.

But today's TV line-up of shows such as Fame Academy and Pop Idol is not proving to have the same level of appeal.

Bazalgette brought Big Brother to the UK

Mr Bazalgette said audiences of seven million viewers for a programme would now be considered a hit.

"Saturday is the one night of the week when most of us now seek bespoke entertainment.

"We don't want a shared experience - we want to design our own," he wrote in London's Evening Standard.

He said his children watched back-to-back episodes of the Simpsons or Buffy the Vampire Slayer on a personal video recorder on Saturday nights.

He added they did not even know what was on terrestrial channels.

Mr Bazalgette's comments follow those of presenter and DJ Noel Edmonds, who called for a "radical" overhaul of Saturday night TV programmes to liven up the schedules.

Edmonds, who is back broadcasting for the BBC on Radio 2, said a "courageous" programmer was needed to turn around the fortunes of weekend teatime viewing.