Over half a century covering major international sport has been an exhilarating experience if not infrequently an exasperating one laced with more than a modicum of cynicism, particularly when the subject of drugs use rears its ugly head.

So, while I was away for a few days last week, why was I not surprised by recent claims that a now struck-off British doctor had provided banned substances for some 150 elite sports figures, among them Premier League footballers, an England cricketer, a British Tour de France cyclist, tennis players and a British champion boxer said to be a household name?

So far there is no corroboration, though the Culture and Sports secretary John Whittingdale has ordered an inquiry and an embarrassed UK Anti-Doping (UKAD), a taxpayer-funded watchdog, have instituted one of their own after suggestions that they knew of the rogue medico’s activities but did nothing about it.

Now I don’t know about the veracity of the report. Even as a journalist I appreciate we should not always believe what we read in the papers, although the Sunday Times, in which the story appeared, have been right on the ball in revealing the skulduggery that has been going on within FIFA and world athletics.

But what I do know is that in a lifetime of involvement in sports reporting I have come to the conclusion that a large number of top sports figures are, or have been, "at it" with performance-enhancing drugs and the majority are getting away with it thanks to masking agents and other medical subterfuge.

For instance, a bulletin on failed drugs tests is regularly dispatched by UKAD. Almost every week this features rugby players, though never a name you might recognise. It is usually a minor club or junior player.

Yet I am certainly not alone in suspecting that there are some very big fish in the game whose physical stature and stamina have been enhanced by more than bench presses and power-lifting. Are they all clean-or just clever?

Worryingly doping is becoming as much a scourge in boxing as it has been for some time in other major sports. The Australian heavyweight Lucas Browne now has a bigger fight on his hands than the one in which he ripped the WBA title from Uzbekistan’s Ruslan Chaegev in Grozny, Chechyna last month.

Browne tested positive for banned fat-burner clenbuterol after the fight yet he had passed a random blood and urine test six days before in Australia and another urine test again the day before the bout in Grozny, something he had personally requested.

As his team point out, Browne ate only at the hotel provided by the promotion and drank sealed bottled water. All very odd.

Nigel Benn, over here for the pro debut of his son Conor last Saturday, and at whose Sydney gym Browne trained before leaving for Chechyna, insists: “There is no way Lucas is a drugs cheat. He was stitched up.” The inference is that Browne’s food or drink was somehow spiked. Chaegev, a favourite of the fight-loving Chechynan President, was strongly fancied to hold on to the title.

Now we learn that Russia’s European light heavyweight champion Igor Mikhalkin has tested positive for meldonium – the cardiovascular "sweetie" of choice for illustrious compatriot Maria Sharapova – following his successful title defence against Patrick Bois in Paris.

"It is true that I have recently taken meldonium," Mikhalkin admits. "Until a few months ago that was allowed, and absolutely consistently in Russia. I did not realize that it is now forbidden. I had stopped it anyway, but apparently it takes a long time until it is completely degraded from the body."

Which brings me to the big-name British boxer who is, or has been, allegedly a client of the drugs-supplying medic.

Who is he? Boxing gyms are notorious rumour-mills but for some time now the whisper has been of a famous name in the sport who actually failed a drugs test that was "hushed up" on condition he served a short ban.

As fighters quite often go for several months inactive between contests this could be feasible.

But I personally doubt the credence of this because surely the Board of Control would have cognisance of the failed test and it is inconceivable they would be complicit in such an arrangement.

I know the name of the boxer around whom these rumours circulate and so do others. But there is absolutely no proof so it cannot be published.

However, I can assure you that it is definitely NOT Anthony Joshua, the new IBF world heavyweight champion, who last weekend became the first Briton to hold Olympic and world heavyweight titles at the same time.

And here’s another curiosity. By knocking out the hapless, hopeless American Charles Martin in four minutes flat he becomes only the second British Olympic boxing champion to hold a world pro title, after super-middleweight James DeGale. A bit like the proverbial number nine bus – you wait ages and then two come along together.

He is a remarkable young man who maintains that winning the Olympic title on that golden summer night in 2012 occupies pride of place over his acquisition of the pro crown. “That was my Spartan night,” he says.

Big Josh is certainly no dope - though perversely he actually does have a conviction for drugs possession in his youth (the recreational variety) that might hamper his career by prohibiting him entry to the United States where the really big money awaits. But he has shaken off this unfortunate episode to emerge as a role model, has an MBE for his Olympic endeavours and now stands at 25 as a young man who his promoters believe can dominate the division for the next decade.

However, we must keep things in perspective. First, brilliant as it is for British boxing, Joshua is not the world heavyweight champion but a world heavyweight champion, third in line as claimant to the genuine status behind fellow Brit Tyson Fury and American Deontay Wilder.

This was a tawdry title plucked from the dustbin where Fury had thrown it disdainfully after being summarily and unfairly stripped by the IBF and, on the evidence of new recipient Charles Martin’s pathetic abdication at the O2, that is where it should have remained.

Even dear old Audley Harrison, another former Olympic champion, recruited as one of the ringside pundits, would have become world champion too had he fought the man who may have called himself Prince Charles but turned out to be a Proper Charlie.

So just how good is AJ. He is a world champion after just 16 fights but the jury is still out.

We have known from day one that he can punch but we do not know yet whether he can sustain his attack and work out his tactics over the championship rounds.

One thing Fury can do is box, and at the moment I have no doubt he would beat Joshua.

The big question now Joshua has a title is who is he going to fight next? The stepping stone days are over. There can be no more bodies - or nobodies.

Popularity-wise Joshua certainly ticks all the boxes and at the moment he is the only one in his camp who seems to be talking any sense.

He’s no fool, he knows he’s got a long way to go. But deep down he must also know that the fella he felled so easily simply didn’t come to fight.