Ennis is not sure whether she wants the Swede to move on and specialise in the long-jump. Kluft is to the heptathlon what Roger Federer is to Wimbledon.

Unbeaten in 18 events and undisputed world No 1 since 2002, when she was 20, she has won the gold medal at three successive World Championships, as well as at the Athens Olympics. She is streets ahead of the field.

Ennis, 21, finished fourth in the World Championships in Osaka in the summer, one place behind fellow Briton Kelly Sotherton. Given the tremendous strides she has made over the last two years, there is every chance that Ennis will offer a far stronger challenge next year, especially as she no longer has to worry about her studies, having graduated in June.

Nevertheless, she clearly doubts her ability to beat Kluft. She just about concedes that she would be happy for Kluft to abdicate her crown, even though a win over a Kluft-less field would surely feel a trifle incomplete, and the Swede's absence would weaken the standing of the event.

"Would I prefer if she did something else?" asks Ennis. "I think a lot of people would be happy if she moved on to the long jump, because the gold medal is always taken by her at major championships. If she's not there, everyone has more chance of a medal.

"It'd be amazing for her to do it and me to beat her but at the moment, she's just so far out there. She's scoring 7,000 points. For me, it would be a massive challenge to put another 400 points on my PB and challenge her.

"Obviously the best thing would be to beat her and win, but to not beat her and win – I'd take that."

The impression Ennis gives is that she would be satisfied with a medal of any colour in Beijing. If the Sheffield-born athlete achieves her goal, she would be catapulted to celebrity status – her looks and affable personality will certainly do her no harm.

After spending the last couple of years on the edge of the limelight, her success appreciated by the athletics world rather than by the wider sporting public, she is aware of what an Olympic medal would do.

"Your whole life would change dramatically," says Ennis, who still socialises with all her old friends from Sheffield. "I don't live like a footballer – I wish. I don't know how I would deal with it. That's something to look forward to but it's not something that drives me.

"I don't like the thought of being really famous. I do get recognised around Sheffield, when I come back from Championships – I get a few people coming up to me and congratulating me."

Ennis certainly does not want to finish in the bridesmaid's position of fourth again next year. She regularly chats to Sheffield-based diver Leon Taylor, who took silver in Athens 2004 a year after finishing fourth at the World Championships. He went from frustration and anonymity to glory and fame.

She says: "Leon says that coming fourth made him more hungry, and that maybe it's not such a bad thing.

"At the beginning of the season, I would have said that fourth would be absolutely amazing. I didn't expect to do as well as I've done this year, but once the competition started going the way it did, I knew I was up there for a medal if everything went to plan.

"My initial reaction was that I was over the moon but that night, I thought 'damn, if I had done a little bit more, I would have got a medal'."

Those niggling thoughts have not disappeared, although she did manage to banish athletics from her mind on a two-week break to the Maldives with her site manager boyfriend Andy at the end of the season, when she proudly states that she managed to do 'absolutely nothing'. Now, she is back in training, mostly at the English Institute of Sport in Sheffield, under the tutelage of coach Tony Minichiello, who has guided her since she was 13. In previous seasons, she studied for her psychology degree from Sheffield University in the mornings and trained in the afternoon. Now, she can train all day and does not have to worry about dissertations and exams – although she is contemplating a post-sport career in clinical psychology.

She should be able to improve her performance, particularly in her two weakest events, the shot-putt and the javelin: at Osaka, she finished first in the 100m hurdles, the 200m and the 800m, third in the high-jump, ninth in the long-jump but a lowly 26th and 34th in the throwing disciplines, despite setting a personal best in the javelin.

Although she is national champion at 100m hurdles and high-jump, her slender 5ft 5in frame is not ideally suited to throwing; her lack of inches made some coaches doubt her ability to be a top-class heptathlete.

Ennis, who got into athletics at a summer camp at the Don Valley Stadium aged nine, says: "A lot of the girls are a lot taller; I'm one of the smallest heptathletes. I was told it could be a problem. It's a bit of a struggle in the throwing events, because my height of release is a lot lower. But I would have thought the major disadvantage would be the high-jump and that's one of my stronger events.

"I'll just keep working. Since graduating, it's such a massive weight off my shoulders – go to bed and not think about all the work you have to do."

The heptathlon is as much about managing a tough two-day programme and coping with the big stage as about expertise in individual disciplines. Having competed at the Commonwealth Games, the European Championship and the World Championships, setting overall personal bests at each, Ennis should be well prepared for the Olympics. However, she does not blithely assume that her upward curve will guarantee her a medal.

"I have been really lucky to have these stepping stones into senior championships," she says. "It's hard to say how confident I am of winning a medal. The heptathlon is so unpredictable. There's a Russian girl, who's only 19, who scored a massive score earlier in the season but got a bit of a knee injury and didn't perform in Osaka and pulled out after the first day.

"There's a Canadian girl that got injured, and a few people dropped out. One bad event can ruin your chances, especially in something like the high-jump. One of the Dutch girls had a disastrous high-jump and dropped out. She would have been up there."

Ennis says she is inspired by her rivalry with Sotherton, whom she looks certain to usurp soon, but insists that the pair get on well, even though Sotherton affectionately nicknamed her 'tadpole' at the Commonwealth Games – they even shared a room at a competition in the summer. According to the former King Ecgbert pupil, heptathlon competitors tend to get on well with each other.

She says: "It's completely different from the sprinting, where everyone's strutting around and keeping focused on what they're doing. We are out there for two days, so you can't be completely focused all the time because you'd drain yourself. We have a bit of a laugh and a giggle.

"There's no bitterness between me and Kelly – although I can think of nicer nicknames than tadpole."

Young frog or not, Ennis could soon be Britain's princess of track and field.

Jessica Ennis receives National Lottery funding through UK Sport.