The Weakest Link is one of BBC One's Saturday highlights

The admissions come as the BBC releases its annual report.

In it, the BBC's governors say: "Saturday night entertainment is still one of the most challenging areas for BBC One.

"No single compelling format has broken through in the year although The National Lottery Jet Set, The Weakest Link Celebrity Special, Comic Relief Does Fame Academy and one-off specials such as Elton John at the Albert Hall have been more successful."

Last Saturday the channel had the hidden camera show Just For Laughs, as well as the World War 2 movie U-571 and the National Lottery draw as part of its schedule.

Shows like Walking with Cavemen have made the BBC millions

Meanwhile, BBC Worldwide has said the Walking with... brand, which has included shows such as Walking with Dinosaurs and Walking with Cavemen, had made the BBC more than �43m after being sold around the world.

The strand has been co-produced with the US channel Discovery.

Walking with Dinosaurs, which was shown in the UK in 2001, has been sold to more than 90 countries. Walking with Cavemen, which was produced this year, has already been sold to over 30 territories.

'New series'

"The Walking with... franchise has been phenomenally successful, gaining huge recognition and audience loyalty around the world," said BBC Worldwide executive Alix Tidmarsh.

"We are looking forward to developing the brand further with new and exciting series that are coming through," he said.

The BBC's report revealed a net debt of �74m but an increase of �346m in spending on programmes.