A lesser-known fact about Daley Thompson is that he is not merely Britain’s finest ever Olympian, but a crucial figure in agitating against the injustice of biological males competing in women’s sport. Long before these Paris Games were scandalised by sex tests revealing two boxers as having XY chromosomes, the male pattern, he was warning of the gathering storm. Quite apart from featuring in a campaign film last year called The Inclusion Delusion, he wrote in a report by think tank Policy Exchange: “We risk alienating a generation of female athletes if we cannot promise them fair and safe play – from the grassroots to the top.”

At 66, Thompson could be forgiven for ducking the toxic blowback this debate unleashes. And yet he feels strongly enough to rebuke the International Olympic Committee for neglecting to protect the female category, prioritising inclusion over fairness. As an illustration, he points to the 33-page “Portrayal Guidelines” document that the IOC have issued to journalists in Paris, advising against the use of such terms as “born male” or “biologically male” on the grounds that such labels are “dehumanising” and constitute “problematic language”.

“You only have to read the statement,” he says. “I don’t understand why they, as the world governing body, don’t take a stance. Instead, they tell everybody else to take a stance and then they chip away at the sides. I don’t understand that.” I point out how Martina Navratilova, the nine-time Wimbledon champion and a steadfast figure in upholding the integrity of female sport, has accused the IOC of Orwellian tactics by waging a “1984 version of war on women”. “Martina knows this inside out,” Thompson nods. “I would agree with that. I would have thought that the defence of women’s sport should be very high on the IOC’s list.”

Sadly, it is anything but. In their insistence that womanhood can be determined by passport status alone, the IOC have created the astonishing situation where two biologically male boxers, Algeria’s Imane Khelif and Lin Yu-ting of Taiwan, are now guaranteed Olympic medals in the women’s competition. They were disqualified from last year’s world boxing championship by the International Boxing Association, who said the DNA of each fighter “was that of a male consisting of XY chromosomes”. Neither appealed against the findings.

I meet Thompson at the Royal Garden Hotel in Kensington, before the eruption of the boxing scandal. But he leaves no doubt as to his views on the IOC’s spinelessness, presenting their failure to ensure a level playing field for women as an extension of their feeble stance on state-sponsored doping. “The IOC, in their different forms over the last 40 or 50 years, have been negligent in their duty towards the one thing they should be looking after, and that’s sport,” he argues. “They allowed the Eastern bloc countries to get away with it in the Seventies and Eighties. They could have done things about China. They could have done more. They should have done more.”

‘Coe would make a good president’

Having seen the convulsions triggered by the IOC’s gospel of inclusion at all costs, Thompson suggests his great friend Sebastian Coe as the ideal candidate to lead the Olympic movement once Thomas Bach steps down next year. Unlike Bach, Coe has shown decisive leadership on the most vexed of questions. In the women’s 800 metre final at the Rio Olympics in 2016, Caster Semenya took gold in a race where all three medallists had differences in sexual development. In response, Coe introduced a policy where any such athletes would have to reduce their testosterone levels to race as women.

“He would make a good president of the IOC, because I truly believe he has the athletes’ interests at heart,” Thompson says. “He does the things he thinks will be beneficial to them. Plus, he has had issues that nobody else has had to deal with. And he seems to have found a good way through them.”

Thompson has been drawn into his febrile sphere through his enduring bond with Sharron Davies. They dated briefly in the late Seventies and have remained friends ever since, with Davies persuading him to champion the cause closest to her heart. While Thompson took Olympic decathlon gold in Moscow in 1980, Davies had to settle for silver in swimming’s 400m individual medley – beaten by Petra Schneider of the former East Germany, who later admitted to having doped. For her, the spectacle of women being wrongly denied medals cuts deep. Fortunately, her ex-boyfriend has not taken much persuading to lend his support.

While gender-ID activists refer pejoratively to their opponents as TERFs (trans-exclusionary radical feminists), Thompson uses it as a badge of honour. “Everyone I’m at my first TERF lunch,” he tweeted last summer. “It was fabulous.” Fiona McAnena, director of campaigns for Sex Matters and the organiser of that meal, tells me: “When non-athletic, middle-aged women say something about this, people ignore it. But when he says something? Well, it’s Daley, isn’t it? First, he is male. Second, he’s a hero. It’s enormously valuable to have his advocacy.”

‘What did you say to Anne?’

Thompson is indeed a British sporting hero. In a poll conducted during these Olympics, Telegraph readers voted for him as the country’s third greatest sportsperson of all time, behind only Andy Murray and Bobby Charlton. A stirring documentary on his life, released last month, introduced a younger audience to the decathlete’s staggering mastery of his 10 disciplines: the detail that he held Olympic, world, European and Commonwealth titles at the same time, that he was unbeaten for nine years, that he strove to maintain his edge by training on Christmas Day.

But where Murray and Charlton both earned knighthoods, Thompson is curiously stranded a rung below, with a CBE. The received wisdom is that he has simply been too strident, too disdainful of authority, to be granted the ultimate establishment honour. There is some logic to this, given his infamous account of an exchange with Princess Anne at the 1984 Los Angeles Games, where he defended his Olympic title. “What did you say to Anne?” a journalist asked him. “And if you are going to have children, who is going to be the mother?” “In answer to your second question, you have just mentioned the lady,” he replied. “And I hope they are white.”

While the remarks sparked a furore, a detail often omitted is that Buckingham Palace described any suggestion of Anne having taken offence as “absurd”. “Thank you,” Thompson says, when I mention this caveat. “The problem was, and I don’t want to be completely disparaging to your career path, is that it was a whole different set of people back then. The attitude of those reporters was that they were the people who could give it to you, and that they were the ones who could take it away. If you weren’t dotting your i’s and crossing your t’s, and attending interviews, they took it as a personal slight. It was completely different to this interview that we’re having. It would have been combative. And they didn’t like it if you weren’t combative back.”

Relations soured to the point where he begrudgingly told athletics writers that he would give them five minutes of his time if they could not name the first five events in the decathlon. “And they couldn’t,” he laughs. “So I was off. They hated it – that they weren’t in charge of my life. But I didn’t do any of it to be famous. I just did it to be the best decathlete in the world.”

It was obsessive, the degree to which he would push himself to physical extremes. Thompson would even keep diaries to ensure every day yielded superior training results to the year before. “I wouldn’t have been comfortable doing it any other way,” he explains. “I never considered it to be a drudge. It was great fun.”

What does he make, then, of athletics’ decision to reward Paris Olympians with $50,000 (£39,000) for a gold medal? Does that not risk diluting the Corinthian spirit? He offers a perhaps surprising answer. “Nowadays it might seem strange that the only people who don’t get paid in this production are the actors. I’m hoping that this is just the start, that it will trickle down. I don’t see why athletes shouldn’t be paid. They produce the greatest festival on earth every four years. It only happens because of them. The Olympics generates billions each year. With money of that magnitude, there’s something for everyone somewhere.”

Claiming to “live vicariously through my five children” these days, Thompson has dialled down the remorseless intensity of old. An evangelist for healthy ageing, he is content with teaching his fitness classes and with imparting his peerless training knowledge to anyone who asks. Marcus Smith, the England rugby team’s superstar fly-half, is one who has already leant on him for advice. “Up until last year, he was still calling me Mr Thompson,” he smiles.

En route to Paris, Thompson has been on a river cruise along the Seine with Sir Steve Redgrave, the fellow Olympic legend with whom he has had a sometimes fraught relationship, once insisting that track and field was a tougher sport than rowing. Do any tensions remain, I wonder. “Not really,” he shoots back, with a devilish grin. “I think Steve understands who the better man is.” Even deep in his seventh decade, the competitive fires have not been doused quite yet.

**Get Shingles Ready is a campaign by GSK supported by Steve Redgrave and Daley Thompson. For more information visit **GetShinglesReady.co.uk