Millionaire show's monster fight

Chris Tarrant: Back with another run of his top-rated show

ITV's blockbuster quiz show Who Wants To Be A Millionaire? returns to the UK's TV screens on Friday - and it has the BBC's ratings winner Walking With Dinosaurs firmly in its sights.

The last series brought British television's biggest-ever game show win when father-of-four Jonathan Green, a firefighter from Essex, won £250,000 after correctly answering 13 multiple-choice questions.

Nobody has yet won the show's top prize of £1m by answering 15 multiple-choice correctly. Contestants have three chances to ask for help as they make their way to £1m - they can have two out of the four options removed, they can ask the audience, or they can phone a friend.

The show, hosted by Chris Tarrant, has achieved ratings of more than 18 million - and the rights have been sold to broadcasters in Spain, Belgium, Germany, the Netherlands, Denmark, Poland, Australia and Russia.

Tarrant with a Royal Television Society award for the show

US network ABC also bought the show and was rewarded with huge ratings for its first run in August. A second series starts on Sunday, with TV veteran Regis Philbin taking Tarrant's role. The highest prize awarded there so far has been $500,000.

In the UK, Celador Productions - which makes the show for ITV - is cashing in further on the show's success by launching spin-off books, a board game - and even a chocolate game.

ITV is pitching the show directly against BBC One's biggest hits, hoping to stop the channel's ratings revival in its tracks.

Monday's edition competes directly with Walking With Dinosaurs, which topped last week's TV ratings with almost 18 million viewers. The following day's edition squares up to that evening's episode of EastEnders, which is currently winning the battle of the soaps.

BBC One controller Peter Salmon said he would never commission such a programme after his channel's audience slumped to just 1.9m on 8 September - under attack from Millionaire and a vital England football game on Channel 5.

Walking With Dinosaurs: ITV hopes to make the BBC's ratings lead extinct

But the show did receive a back-handed compliment from the channel's comedy hit The Royle Family - which based an entire episode around one edition of the quiz.

Bookmaker William Hill is offering 10-1 against a single competitor winning £1m - and one London punter has bet £100 that the top prize will be won by the end of the year.

Host Chris Tarrant said: "You can almost feel people at home shouting the answers at their TV screens, then there's the excitement of actually watching someone win a huge amount of money.

"It's also a living soap opera - we've thrown up some really colourful personalities.

"I can't wait until someone wins £1m. I know it will happen sometime, and when it does, it's bound to be fantastic to watch."