For Christmas a few years ago, former Olympic swimmer Sharron Davies received a very unusual present from her father, Terry. Secretly, he had taken her Olympic silver medal and had it dipped in gold plate. It was reparation, he said, for the injustice Sharron suffered at the 1980 Olympics when an East German doping cheat beat his 18-year-old daughter by 10 seconds in the 400m individual medley.

The British swimmer, now 60, has been seething ever since. But now she has a new injustice to battle, one that is, she says, damaging sport just as much as performance-enhancing drugs: male athletes who identify as women in order to compete in female categories.

Trans ideology, she claims, is robbing women of podium places in many different disciplines, as trans-women born with naturally larger and stronger bodies overpower their female competitors – on the field, on the track, and in the pool. What’s worse is that it’s a situation sanctioned by the International Olympic Committee (IOC).

“This means that a biological male athlete can call themselves a woman and transition to a new status ahead of female Olympic athletes overnight,” says Davies, who also won six Commonwealth Games medals during her career and was awarded an MBE in 1993.

“Gender is a social stereotype and sex is a biological reality in which the presence of testosterone gives an unfair physiological advantage.”

She is sympathetic to the feelings of transgender people but adds: “Where do we stop with feelings being more important than reality? A feeling cannot trump a biological reality. A transgender woman is biologically male and will remain so for the rest of their life. Biological sex remains important when it comes to medicine, statistics, and sport – however someone chooses to identify.”

Born and brought up in Devon, Davies first competed in the Olympics in Montreal, in 1976, at the tender age of 13. On retiring from professional swimming she became a TV celebrity, commentating on sports events and competing as Amazon for a season of the nineties game show Gladiators. Three-times married, she remains utterly striking and statuesque.

But she has been campaigning for equality in sport ever since she was robbed of her gold medal at the 1980 Olympics in Moscow, when she lost to Petra Schneider.

The East German later admitted her victory was drug-enhanced following a doping scandal among young female athletes who were forced into male puberty with synthetic testosterone jabs. The officially-sanctioned cheating made the German Democratic Republic the most successful medal factory in Olympic history.

Davies has always had huge sympathy for the young East German victims, despite the impact on her own legacy.

She also has deep concern for the current generation of young sportswomen. “Now we are looking at the same end result: girls who should win races will no longer win them. Whole lives will be affected,” she tells me. It is this she prefers to focus on, rather than the travesty of coming second 43 years ago. I’m lucky,” the respected BBC sports pundit says.

“My career has given me a nice house and a successful life, but I can’t just sit back and let it happen to another generation.” Her principled stand, which has cost her work and made her a hate figure in some circles, is compellingly debated in a fascinating new book she has just published, Unfair Play: The Battle For Women’s Sport.

Her arguments are strengthened by research revealing the current situation is “worse than doping”.

“Doping girls with testosterone to put them through male puberty gave a nine per cent advantage in swimming, but allowing biological males who self-identify as women is even more extreme,” she explains.

“It can confer up to a 30 percent advantage in explosive sports like weight-lifting, 12 percent in sprinting, and add 11 percent in the water.”

Testosterone affords such a physical advantage that it has previously been described as “functional doping”. For agreeing with the science behind such statements, Davies has received online trolling and hate mail. She bats it away, gritty professional that she is.

“I’ve always had negative commentary,” she says breezily. “And it always makes me more determined when they are vile
and rude and ignorant, to be polite and respectful, which I always am. Stay calm. Present the facts.

“They come online and fling a load of insulting words at you, and on the whole it’s men. I do feel that [the trans-activist movement] is quite misogynistic.”

Conversely, many people write to her and talk to her on the street, agreeing with her opinions, which “mitigates the trolls”.

The day she talks to the Daily Express, however, she was still politely annoyed about an earlier television interview to promote her book. “The first thing they talked about was the feelings of transgender athletes. I believe in sport for all, but no one talks about the feelings of young women who have trained for years and are being robbed of opportunity,” she says.

“If you win in sport, you get scholarships to universities in America, you get marketing, you get to put it on your CV for the rest of your life.

“This isn’t just a flippant little thing. When we are all encouraged to ‘be kind’ in this situation, the only people losing out are female athletes.

“Why does a transwoman have to be female? Why can’t we show respect for them as a new category? When women, who have trained hard all their lives, see a male of average ability self-identifying as the opposite gender, without surgery, and being given a ticket to the top of female sport, it is incredibly unfair and is impacting entire futures, including the livelihoods of our female athletes.”

Davies is equally concerned the contentious 2015 ruling by the International Olympic Committee on self identification has had an effect on sport at all levels.

She explains how some male runners and cyclists who identify as women post their personal bests on sports apps such as Parkrun and Strava, which in turn obliterates the course records of legitimate female athletes.

Only last month, it was revealed that an athlete who smashed a women’s Parkrun record in the 45 to 49 age group category had been living as a married man until just over four years ago.

“There is no check system in place,” Davies continues. “I don’t get why the apps can’t add a box to have a new trans category?” She is at pains to make clear how much she believes in sport for all. Davies has friends who are transgender, as is a close friend of her daughter.

“The last thing I would ever want to do is take away anyone’s interest in sport. I’m passionate about creating opportunity for all; I just want to see fairness.”

She points out that, in the UK, less than 1,000 women earn a living from sport compared to just under 11,000 men. Meanwhile, in the US, women receive just one per cent of sports sponsorship money.

“Women have a tiny little chunk of the world’s opportunities in sport,” she continues. “Now they are being asked to move over for people who we know already have a biological advantage. This is not fair.”

While pleased that Prime Minister Rishi Sunak has spoken out about protecting women’s sport, Davies challenges him to be “more forceful” in insisting on equality.

“We need to clarify the Equality Act,” she says crisply. “No one ever thought we would have to insert the word ‘biological’ to clarify the law. But we need it so that we have the ability to go to court.”

She insists that if there is sexual discrimination, she herself will pursue the offenders through the courts. Davies is particularly concerned that a commitment to inclusivity is wrecking the chances of a whole generation of girls.

“Separate categories for girls and boys increasingly don’t exist in many primary schools,” she says. “I’ve had parents calling me in tears about sports days where not a single girl has won a race. The only message that sends is that little girls don’t win. And it’s happening more and more.”

Certain sports governing bodies, such as World Athletics and FINA (swimming), have woken up to the problem, banning transgender female athletes from competing in female competitions. Davies says it is “unbelievably disappointing” the IOC hasn’t followed suit.

She is convinced there is a “silent majority” in this country who agree with her stance, but believes the current obsession with cancel culture makes many too nervous to share their position publicly.

“This would be solved very quickly, but unfortunately, the vast majority stay quiet,” she adds. “I can afford to speak out but by doing so I have been called a racist and a sexist. How can I be? I’ve been involved in sport since I was a little girl.

“I don’t see colour, sex, religion or sexuality. I judge people 100 per cent on who they are and how much they try, but the moment anyone can self-identify as a woman, how can females be protected?”

She admires the bravery of Harry Potter author JK Rowling, who has also been pilloried by trans-rights activists and others for putting the needs of female abuse victims ahead of transwomen.

“She is a very strong lady who has done so much wonderful stuff,” Davies asserts. “She is not anti-trans, she is pro-women, and she is creating rape centres for women who are traumatised by sharing space with biological men. My area of expertise is sport, however. I know it inside out and you do have to understand the science to have this debate and accept that performance is based on the reality of your physiology.”

She explains how trans self-identification is “destroying the integrity of female sport. If you endorse it, you are expecting female athletes, who have been training all their lives, to line up with athletes born male.

“In swimming, male and females have always trained together but they don’t race each other. In boxing, heavyweights don’t compete against featherweights.”

Compellingly, she stresses how there are “100 years of Olympic results that show men run, swim and throw further than women”.

“Why would we even have male and female competitions if there was no difference?” she concludes. “The whole point of a category is to give everyone an opportunity to win. After all, if there were no categories in sport, the only winners would be fit young men.”

• Unfair Play: The Battle For Women’s Sport by Sharron Davies and Craig Lord (Swift Press, £20) is out now. Visit expressbookshop.com or call Express Bookshop on 020 3176 3832. Free UK P&P on orders over £25