SUPERMAN can fly, Spider-Man swings from one skyscraper to the next, but Doctor Who might just top them both.

Sure he's biased, but Tennant's love for Who stems from a childhood adulation of superheroes. Funnily enough, it was our Dalek-duelling Doctor who most impressed him.

"There is something about that character. It is the fact he is a free spirit, coupled with his absolute moral certainty and he is the cleverest guy in the room," Tennant says.

"I used to love the Marvel comic heroes, but they were the fastest, the strongest, the ones who could fly.

"The thing about the Doctor, that's not how he operates. I think he's something to aspire to. He's just about living off his wits."

Little wonder a young Tennant aspired to be like his idol. "He is the ultimate geek hero and I was the kid with specs and a poor haircut. I was never going to be Superman, but maybe I could be more like the Doctor."

New episodes of Doctor Who kick off on Thursday with the one-off special, The Runaway Bride (which aired last Christmas on the BBC) and the third series starting on Saturday.

Tennant is the 10th Doctor, taking over control of the Tardis from Christopher Eccleston. The pressure of measuring up to what the fans want out of a Doctor was never going to be easy. The amount of attention and the weight of expectation from a British public who view the Doctor as a cultural institution proved hard, Tenant says. "There is a daunting aspect to taking that on. However you might pretend you're not bothered by that, it is difficult. You do have to take a deep breath."

Tennant realised the importance of putting his own stamp on the role. The first step was getting the look right. It took numerous outfit changes before Tennant settled on that snappy suit. "You scramble towards your own interpretation (of the Doctor)," he says.

But Tennant has proved a fan favourite, recently voted the best doctor by readers of Doctor Who magazine. "Even to be on the list is strange," he says, humbly. "It was a very surreal, but very pleasing moment. (But) I'm not pretending this proves I'm the best. I wouldn't be so arrogant as to suggest that.

"I'm just delighted the fans aren't burning effigies of me in the street. To take on the role of Doctor Who and escape with my credibility was all I wanted to do."

Although known mostly for his role as the time-traveller, Tennant is an accomplished stage actor and has even appeared as the evil Barty Crouch in the movie, Harry Potter And The Goblet Of Fire.

In the previous Doctor Who series, we said goodbye to the Time Lord's companion Rose Tyler (Billie Piper). This series we welcome newcomer Martha Jones (Freema Ageyman).

Tennant says the series explores Martha's background and we get to meet some strange intergalactic storm troopers who have rhinoceros heads in the first ep. The Daleks also reappear.

There has been speculation that Tennant will leave somewhere through the course of the fourth series, but he laughs off such talk.

"From the moment I took the job there has been speculation I was leaving. It's one thing you have to expect," he says. "I'm having the time of my life and I wouldn't want it any other way at the moment."

* Doctor Who: The Runaway Bride, Thursday, ABC, 8.35pm; third series, Saturday, 7.30pm

Source: The Daily Telegraph (Oz)