I believe him. The problem is, millions don’t. Most of them in France.

Unfortunately Froome is a victim of the festering legacy left by Lance Armstrong. No matter how clean he says he is, a sceptical world will continue to believe it was achieved by the use of drugs, especially in view of the literally breathtaking nature of some of his stage wins.

Just as they do with Usain Bolt’s track records.

After more than half-a-century of covering sport in all its glory - and infamy - my cynicism is ingrained but in this instance I prefer to believe Brailsford. He is a decent, straight-up guy, and one of the few sports administrators I would trust with my life.  

If he says Froome and his team are clean, then they are. And I pray Bolt is too.

Because if either were to fail a drugs test now or in the future their respective sports would be torn apart, perhaps never to recover.

In the case of va-va Froome and his intensely supportive Skymen a positive test in would be a fatal spoke in British cycling’s current wheel of fortune.

For the success of cycling and its rise in popularity in Britain after the 2012 Olympics is quite phenomenal. And that could be part of the problem. For with success comes suspicion and envy.

There has been a healthy surge in cycling as a pleasure pursuit. Interest in the sport has never been greater, led by the Mayor of London and his Boris bikes.

The figures are quite staggering. Those dozen medals - eight of them gold - at the London Olympics have led to a five-fold increase in membership of cycling clubs, with an extra 1.7 million people getting on their bikes since 2012.

However this has also created a certain amount of alienation and antipathy towards the sport among other road users as more than a few nouveau- bikers seem to think they are above obeying the normal rules of the road, notably at traffic lights. Not to mention those infuriating road closures in London and elsewhere whenever even a minor race blessed by Boris is in progress.

Not that this is Froome’s fault. Brailsford, the brilliant architect of Britain’s pedal power, has supervised three British Tour de France wins in the last four years.

He says the Kenya-both Froome’s latest was the greatest of all, arguing: ”He deserves recognition as one if the best British sportsmen Britain has ever produced.”

I second that and so far there is not another candidate for Sports Personality of the Year within loud-hailing distance.

Stoically he pedalled on through a gauntlet of Gallic resentment - the French themselves have not won a Tour since 1985 so how they must hate to see a Brit so supreme at their national sport.

Froome had encountered volleys of obscenities, innuendo, spittle and even urine and said wryly when beer was thrown over him it was the first drink he’d had since Christmas!

Of course the French have long memories, dating back to 1967 and one of the Tour’s first doping sensations when another British rider, Tommy Simpson, collapsed and died during the ascent of Mont Ventoux during the 13th stage of the Tour.

The post-mortem examination found that he had taken amphetamines and alcohol, a diuretic which proved fatal when combined with the heat, and the hard climb of the Ventoux.

At Stratford’s Olympic Park some 48 hours earlier no-one spat into Bolt’s face and screamed that he was a drugs cheat. Though the malicious whispering lingers behind his back, just as it does Mo Farah’s.

The build-up to Bolt’s appearance in the Anniversary Games, for which he was paid £150,000 ($234,000/€212,000) was such that it would have been no surprise had they hired the most celebrated of MCs, Michael "Let’s Get Ready To Rumble" Buffer, to make the introductions.

Like Froome, Bolt must feel he is carrying the reputation of his sport on his shoulders.

Lie Froome too, he is adamant that he is as clean as the proverbial whistle, and there is not a shred of evidence to suggest otherwise. If there are doubts both deserve the benefit of them.

Yet those doubts will not disappear as long as Froome keeps on pedalling and Bolt keeps on running. Very fast.

In his book The Bolt Supremacy author Richard Moore quotes TheNew Yorker magazine which in 2013 compared the sprinter’s status to that of Armstrong before his exposure. Bolt is portrayed as “a man dominating a dirty sport as his rivals and team-mates fall”. The magazine suggested: “It wouldn’t be a surprise if one day this summer Bolt starts talking about misreading the label on a herbal supplement – or if, a decade from now, he ends up talking to Oprah.”

Over the years the Jamaican had consistently worked hard to prove himself better than those known cheats who kept taking the tablets. But for how much longer?

With the World Championships a few weeks away he needs to  sharpen his form if he is to see off one of the most serious former fraudsters of all, the twice-convicted American Justin Gatlin, who, at 33, is amazingly running faster than ever and ominously faster than Bolt. He may even start the 100m final as favourite.

Bolt v Gatlin in Beijing is now taking on the proportions of Coe v Ovett. Or even Ali v Frazier.

It is imperative that Bolt trounces Gatlin as his mission must be to convince a sceptical world that genuine athletes can finish ahead of those who in the past have received pharmaceutical assistance.

Meantime the never-ending catch-me-if-you-can- chase between the bottle-wielding doping authorities and the chemically-enhanced continues. The most heartening aspect is that so many are being caught. In Britain, anyway.

Barely a week passes without a rugby player from either code being banned for using illegal products.

For some time now I have suspected that rugby players are the worst doping offenders in British sport. You need only to look at some of them to know that they pumping more than iron to achieve such massive physiques.

The danger is that a couple of positive tests during the upcoming rugby union World Cup could see the event become mired in scandal than celebrated form kits sport.

UK Anti-Doping (UKAD) have now confirmed that the undefeated European, and Commonwealth and World Boxing Council (WBC) international super bantamweight boxing champion Kid Galahad (real name Abdul Barry Awad) - he was voted Britain’s Best Young Boxer last year - has been suspended from all sport for two years.

His plea that his drink was spiked by his brother after an argument over money was not accepted as a legitimate excuse. The 25-year-old Sheffield fighter tested  positive for stanozolol, an anabolic  steroid that was the favourite performance-enhancing tipple of Ben Johnson.

Galahad is now stripped of his titles but the Boxing Writers’ Club say he will keep their Best Young Boxer trophy as the vote was conducted before the result of his failed drugs test was known.

UKAD’s chief executive, Nicole Sapstead, says: “All athletes, at all levels, need to understand the importance of Strict Liability – they are solely responsible for any banned substance that is found in their system, regardless of how it got there or whether there was an intention to cheat or not.”

Drugs taking is a menace in all in so many sports these days and alarmingly is becoming increasingly prevalent in boxing. According to UK Anti-Doping 19 boxers have failed drugs in Britain in recent years, four of them amateurs. The substances involve range from cannabis and diuretics to steroids.

Six boxers, now including Galahad, are currently serving bans. So Galahad’s punishment as boxing’s biggest fish to be caught in the drugs net here is a stark warning to all British boxers to confine any rope-a-doping to the ring.

As for the current twin towers of global sport, Froome and Bolt, the debate will rage among the sceptics  as to whether they as squeaky clean as they maintain, or  simply clever.

One would like to think that when it comes to the ultimate test, that as Oscar Wilde famously said, they have nothing to declare but their genius.