ACCORDING to Chris Tarrant, presenting Who Wants To Be A Millionaire? is a bit like the interview we're doing. He's right, up to a point. We are sitting facing each other and questions are being asked, but I'm the one putting them, no-one can win a million pounds, and phoning a friend isn't an option.

The show returns to ITV1 tonight, after winning the most popular quiz show prize again at the National Television Awards this week.

"I sit opposite some geezer I don't know from Adam and we're playing for money that could completely and utterly change your life," he says of Millionaire, which has given away £45m (and made four people millionaires - five if you count the cheating, coughing major). The format has been sold to more than 100 countries.

Tarrant attributes the worldwide success to contestants representing a wide range of people, feeling it's known as "the people's quiz show" for that very reason. Other game shows pick and prepare contestants, whereas anyone can appear on Millionaire just by answering a qualifying question.

When the show debuted in 1998, no-one could have predicted the scale of success. "We thought it would do all right because it's such a perfectly simple format and the money was an exciting ingredient," says Tarrant.

"What we didn't see coming, because it's shot in those big close-ups with the music, was the human drama. Game shows are usually shot big and wide. This looks right into the soul with all the sweat and shocks."

He admits he can be very boring about Millionaire, reeling off facts and figures to prove the point. He's pleased it's the most successful game show ever, mainly because they hate that fact in America, where they invented the game show.

He rejected the presenter's job on the US version. "If I'd been younger, I'd have gone but I didn't want my kids to grow up in New York or live there six or seven months with the kids back in England," he says. "I was offered the Australian one and would have done it except I was under contract to Capital Radio."

The one question he can't answer is how much longer Millionaire will continue. "It will never again get the 19m viewers it got back in 1998," he says. "What it has done is settle nicely and steadily in the Saturday schedules getting six, seven, eight, even nine million a few times last year. There's a good hardcore audience. I've always said I will carry on doing it as long as there's a market for it. I thoroughly enjoy it."

Presenting Millionaire is only the latest successful role in Tarrant's showbiz career. The former ATV reporter in Birmingham changed the face of children's TV with Tiswas and then spent 20 years on London's Capital Radio, 17 of them as breakfast show presenter. He was so much a part of the station's success that his leaving affected the company's share price.

Radio brought him to Newcastle this week, backing a bid for the new North-East radio licence from Celador Radio Broadcasting, part of the Celador empire that produces Millionaire.

This was no hardship for Tarrant, who's passionate about radio, both working in it and listening to it. "My test of great radio is when I sit in a dreadful traffic jam and suddenly think of something Kenny Everett said 20 years ago. That's remarkable radio," he says.

Everett is his radio hero, although Tarrant himself became inseparable from the Capital breakfast show. He fears people trying to dumb down radio, trying to depersonalise it. "In the end, radio is about people on the radio. You can have all the playlists in the world but it's about the people between the tubes," he says. "For me, radio was a buzz."

IT was a shock moving to radio from TV, where a simple interview would involve a dozen or more technicians due to union restrictions. "There was me, a pile of records, a few pieces of paper and a producer," he recalls.

"It was such a very different discipline. Radio was a real shot in the arm, I used to really look forward to it."

As for those who claim you can't do both radio and TV, he points to Terry Wogan and Noel Edmonds as living proof that you can. Not that he pretends there's a lot to radio presenting. "It's not very hard - don't tell anybody. One of my beefs is that people over-analyse things and presenters are being told what to say," he adds.

He left Capital 18 months ago in happy circumstances, sensing that a really unsettling period was on the way. He was proved right, with ratings and money becoming increasingly important in the industry.

Millionaire and another ITV show, Tarrant On TV, keep him busy. He's also halfway through filming a TV series in which he and wife Ingrid tour the country in her father's 1936 Bentley convertible. A regional series proved so popular that it's going nationwide.

Tarrant has been ticking off things on his list of things to do after leaving Capital. Like an expedition to see polar bears. He'd seen brown ones and grizzly ones on fishing trips abroad. A trip with a mate ended up with a photographer and film crew joining them.

A documentary charting their search will be seen on ITV over Christmas.

"It turned into one of the most exciting three weeks of my life," he says. "We saw two or three but the one we won't forget came swimming towards us when there were four of us in an inflatable boat. I thought we were going to die. There are only a few species that will hunt and eat a man, and polar bears are one of them."

He survived the encounter - the bear made warning noises but didn't attack - and is eager to follow the David Attenborough wildlife route, with ambitions to film orang-utans in Sumatra and gorillas in Rwanda next.

His last visit to Newcastle also involved a boat trip and wildlife. He went fishing on the Tyne with former cricketer Ian Botham. It was less rowdy than previous visits to the city with the Tiswas roadshow to the university on a Saturday night.

l Who Wants To Be A Millionaire? returns to ITV1 tonight at 8.10pm.