The first time Pep Guardiola’s legacy was threatened by serious accusations of cheating, it took eight years and some vials of unstable urine to clear his name.

We’re going back a fair while for the retelling of this tale. In fact, we’re rewinding all the way to the autumn of 2001, when Guardiola was aged 30 and had rocked up at Brescia in Serie A near the end of his garlanded days as a player.

Many will know the broader brushstrokes of the storm that came next but possibly not the extraordinary details. In other words, there might exist a faint memory of his two positive drug tests for small amounts of the banned steroid nandrolone but not his journey to exoneration.

Now that was a proper legal saga. At different stages, Guardiola was given a four-month sporting ban and a seven-month suspended prison sentence, but he maintained his innocence all the same. He challenged the findings, lost an appeal that had been based on a contamination defence, and after several years pivoted to something else entirely.

To review some excellent reporting from the investigative journalist Edmund Willison, the genesis of a new strategy came from a former Olympic polo player, Manel Estiarte, one of Guardiola’s closest friends and later a hugely-valued confidante on his backroom staff at Manchester City. His thesis? Unstable urine.

You see, Estiarte had evidently become aware of research conducted around 2005 that showed rare cases of low-level positives for nandrolone, brought on by chemical reactions when urine is stored in vials. Guardiola’s team started exploring the route and the courts agreed it was a valid line of concern. That led into a decisive phase, when it was then discovered that the samples couldn’t be retested for instability because there were no samples left to examine.

Pep Guardiola was exonerated from a doping charge after a lengthy eight-year battle 

Guardiola staunchly maintained City’s innocence and said he would walk if he had been lied to

First, the criminal conviction was wiped out in 2007 and then, in May 2009, 12 months after he was named manager of Barcelona, the sporting sanction was scrubbed from history, too. After eight years, Guardiola was completely cleared on all charges and the course of modern football would go on to change forever.

Looking back from today’s vantage point, that was a remarkable episode for a couple of reasons – one is the nature of the events that spread across the thick end of a decade and the other is how few people ever discuss it. In different sports, the court of public opinion can be unforgiving, even when the final reckoning is innocence, but in football the walls tend to be coated in Teflon. People move on fast.

Why is this relevant now? Because the theory faces its greatest test – there is no suggestion that Guardiola knew what his bosses were up to at Manchester City but his many achievements will be skewed through the prism of their wrongdoing nonetheless.

Manchester City won’t get any benefit of the doubt from neutrals in the public – for all their ongoing protestations of innocence, the image of that club is in ruins. Smashed. Destroyed.

Pending their inevitable appeals, everything they won in their years of Abu Dhabi ownership belongs under the weight of the heaviest asterisk ever imposed in British sport. If those appeals fail and it becomes indisputable that City doped their finances on a grotesque scale, relegation should be the starting point of any conversation about what comes next.

But Guardiola’s legacy is of sharper concern in my mind. What will this mean to one of the greatest thinkers that sport has ever known? In short, it is impossible to separate the beauty of what he delivered from the cheating, lies and institutional filth that appears to have enabled it.

The eras now live as links in a sordid chain of questions – without cooking the books, would City have got Roberto Mancini? Without Mancini, do we get that Aguerooooo moment in 2012? Without Aguerooooo, do we see Manuel Pellegrini and three more trophies? Without Pellegrini, does Guardiola step in? Without Guardiola, do City sign Erling Haaland? Without Haaland is there a treble?

I loved watching Guardiola’s City. It was sporting excellence. It was art mixed with science mixed the head-scratching madness of the man who designed it; the disciple of Cruyff and his truest heir.

Was Guardiola the greatest coach we have known in the Premier League era? By the time he left, I was starting to lean that way, but football is a results game. And results need to be trusted. But we cannot trust those results and that means everything Guardiola achieved at City, all 20 of his trophies, is tainted by an unwitting association with cheats.

He has been robbed by them, but so have we. So have City’s rivals, who will now assemble lawyers of their own and kickstart the chaos of compensation claims.

My view is that the most fitting outcome, once the appeals are done, is that City’s entire list of prizes from the commencement of the Abu Dhabi regime until now is expunged from the record. They should be scratched out like Ben Johnson and Lance Arsmstrong, because doping the accounts in modern football is no less beneficial than doping your blood if you’re a sprinter or cyclist.

He left last summer but he should publicly shame his former bosses if he wishes to salvage his reputation

The only difference I would put forward is that the titles should not be reallocated – leave them blank to signify this situation for what it is. One of no winners. We all lose, Guardiola and his beautiful mind included.

We should remember at this juncture that he defended his club to the hilt. And of course he did. But he also said if they were ever found guilty, he would walk. His resignation overtook that possibility.

But he still has the power and populist capital to punish them. He can’t walk away from what he has already left, but he can confront the executives responsible. He can shame those friends of his who lied to his face and left his reputation among the debris of their deception. 

If he is half as righteous as he had us believe, he would do just that, because the mud of this scandal will coat him as much as Manchester City. It won’t be forgotten.

I’m unsure if I’d sacrifice a pot of unstable urine in the club’s word at present. But Guardiola can still do some good with his.