It is testament to the unpredictability of sport that Jemma Simpson went to the Commonwealth Games in Melbourne three years ago with high aspirations and ended up with a bit-part in Neighbours. She is clearly not your average athlete, both in terms of an ability that puts her at No 6 in the world at 800 metres and in terms of a story that encompasses collapsing feet and a homicidal albino monk.

She also bucks the trend for anodyne answers by proffering opinions on everything from Kenyan marriage to why Japan holds the key to a clean Olympic Games in 2012. First things first. She starts the Aviva World Trials in Birmingham on Thursday evening as the fastest woman in arguably the most competitive event in Britain, her time of 1min 59.31sec in Madrid last week bringing down the curtain on a horrible 12 months.

“I had a stress fracture of my navicular [mid-foot bone] and every time I got to the end of a race my feet would collapse,” she said. “Once the lactic acid kicked in, I just lost all form.”

It did not help at the Olympics in Beijing, where she went out in the heats, but she rejected the easy excuse. “I messed up my tactics,” she said. “I’m more an endurance runner and that turned into a 300-metre sprint. I should have had the confidence to control the race.”

Simpson was limping around for days afterwards, though, and had to rebuild her left calf and foot. That comprised an enforced sabbatical and holding four times her weight on a leg press. She then followed Mark Rowland, her coach, when the Olympic steeplechase bronze medal-winner took a job in Oregon. The weather was the same, the attitudes incomparable. “Everything is positive in America,” Simpson said. “Here, you ask someone how they are and they say, ‘Not bad.’ There, they say, ‘I’m great.’ That filters through. It’s a British thing, but we should be as confident as they are.”

It may be this optimism that informs her opinions about doping. The 1,500 metres, which is likely to be her ultimate destination, has been destroyed by Russian drug cheats. The IAAF, the world governing body, is awaiting the Court of Arbitration for Sport to decide whether to indulge Russia’s cynicism and backdate bans to free the cheats to compete at the World Championships in Berlin next month. With 29 Russians banned for doping, isn’t that depressing?

“No, it’s good,” Simpson said. “The more they catch, the better. You talk about it with other runners and you have suspicions, but you can’t let it affect you. It’s not a level playing field, but the more positive tests there are, the more likely we are to have a clean Games in 2012. You need the stigma. Japan never seems to have a problem and I think that’s probably because it would be considered a terrible thing there. That’s the way it has to be.”

But what of Britain, given Dwain Chambers is vying for a place in the Great Britain team today? “I honestly don’t think British athletes are doping,” Simpson said. “Our controls are so strict now. It’s not the culture.”

Simpson, 25, will surely make the team, even if she does not beat Marilyn Okoro and Jenny Meadows for the one automatic place at the trials. Having been to all the leading championships, she knows that she needs to start reaching finals and wants to be a serious medal contender by 2012. The good news is that the 800 metres vista is changing, with Pamela Jelimo, last year’s sensation from Kenya, having a torrid start to the summer. Meadows beat her in May before Simpson finished four seconds ahead of her at the Prefontaine Classic in Eugene, Oregon, last month.

“She’s already set up for life and she’s quite young to come on the scene and suddenly get everything,” Simpson said. “She might keep her head down and keep going or she might go off the rails. She’s also married and when Kenyans get married, that often has an impact on their running. They start building farms.”

Simpson is far from the blinkered obsessive. After the Commonwealth Games she was out running with Stuart Stokes, a team-mate, when they spotted Ian Smith, who plays Harold Bishop in Neighbours. Before they knew it, they had been invited on to the set and were coffee-shop extras. Then a friend’s mother was doing the make-up for Silas, the mad monk, in The Da Vinci Code. Hence, Simpson became a student as Tom Hanks gave a lecture in a London film studio. She has no higher ambitions in the thespian world, but does plan to come in from the wings and take centre stage.