‘I was reminded of Andre Agassi last week when The Times published a great photo of Maria and her friends from Nike. He’s sitting on the back of the car with Roger and Rafael, Pistol Pete and Big Mac, just a big happy family’ Photo: Gary Gershoff/WireImage

Murray's decision to speak out against such goings on has not been met with great enthusiasm by the former British tennis player Andrew Castle, who criticised Murray for going public with his claims. "I think he has been unguarded and naïve. If he has these claims he should take them to the ATP officials. Tennis has been thrown into something that doesn't make the game look good." The Guardian, October 2007

Eight years ago, a month after Andy Murray had voiced some concerns about match fixing in tennis, John McEnroe, one of the sport's greatest players and its foremost commentator, was giving a press conference at a masters event in Liege when he became embroiled in an ugly spat with a German reporter.

"It has been said that players have admitted fixing matches. What's your opinion on this?" the reporter asked.

"What? Who? Do you have any names? Proof?" McEnroe snapped.

"They're rumours that I've heard about or read," the reporter blushed.

"You're joking!" McEnroe erupted. "You should get your facts right before asking the question. And why tennis? What about football? Are there no matches sold in the Bundesliga?"

It was a reminder of how the sport has always conducted its business: Pro tennis, the American author Michael Mewshaw once observed, could teach the mafia about omerta.

Take the directive issued by the Women's Tennis Association (WTA) last week to players at the BNP Paribas Open at Indian Wells and published on Wednesday by Sports Illustrated. In the wake of Maria Sharapova's failed doping test, players were reminded that "any and all" media enquiries should be directed to a WTA official. They were also provided with some sample questions and advised how to respond:

Q: Do you think Maria should be suspended?

A: We think it's important that the Tennis Anti-Doping Program follows the standard procedures it has in place. The WTA will support the decisions reached through this process.

Q. Does it surprise you that this happened to Maria?

A. Every player received the 2016 WADA Prohibited List from both the WTA and ITF. It is the responsibility of the player to know the rules

Q. Is Maria right? Was her medication allowed prior to January 1 and was it added to the banned list on January 1?

A. Yes it was prohibited as of January 1.

Q. If Maria can't play anymore, how much of a blow is that to the WTA?

A. I'm not prepared to speculate about the future. I think it's important for the TADP to complete its process and render its judgement.

Q. Between this and the gambling revelations, it's been a tough year for tennis.

A. The integrity of our sport is paramount and it is important to do the right thing and follow the rules. I think the future of tennis is very bright and the game remains very popular around the world. I thought Maria did the right thing to let people know about this herself, but now it is important to let the TADP carry out its procedures. We have a comprehensive process in place and I have confidence that the results will reflect what is appropriate.

It's called singing from the same hymn sheet.

Tennis has always washed its whites in private - the only surprise about the Sharapova case is that we were told about it. On Tuesday, Roselyne Bachelot, the former French minister for health and sport, became visibly irritated when the subject was raised during a debate on TV. "We never hear about positive tests," she said. "We just learn that players pick up injuries that keep them off the courts for months."

On Friday, she expanded on her comments in a statement to Le Monde: "It has been proven that suspensions or the end of careers - supposedly for health reasons - have served to cover up positive controls and been agreed by the players, their entourage and the tennis authorities. We can only hope that Madame Sharapova's declaration opens a new era of transparency in a magnificent sport where financial gain has often been the source of temptation."

Toni Nadal, the uncle and trainer of Rafael Nadal, was incensed by Bachelot's statement: "That woman is an imbecile," he said. But Sharapova didn't agree: "I won't pretend to be injured so I can hide the truth about my testing," she said, reaching out to fans on her Facebook page.

And it's not like we haven't been here before.

In November 2009, Andre Agassi made headlines around the world when he revealed in his autobiography Open that he had tested positive for crystal meth in 1997, lied that it had been ingested accidentally, and been absolved by the tennis authorities.

The ITF weren't pleased and immediately issued a statement: "Such comments in no way reflect the fact that the tennis anti-doping program is currently regarded as one of the most rigorous and comprehensive anti-doping programs in sport."

They do have a sense of humour.

A month later, on a Wednesday afternoon at the Mandarin Oriental hotel in London, I sat down with Agassi over a coffee (me), a Coke (him) and a plate of salted almonds. I told him a story about some agonising I'd done when Open had been published.

"I was in the bookstore and picked it up and had just reached the till when a thought entered my head: 'I don't know if I want to read this. What if it's bullshit?' What if I'm being sold another Lance Armstrong?"

(I handed him a copy of It's Not About the Bike.)

"Have you read it?" I asked.

"I'm embarrassed to say . . . are we off the record?"

"Sure."

(I liked him immediately.)

We went back on the record and I finished my story. "So I didn't buy the book but a week later, a friend whose opinion I really respect, told me it was absolutely outstanding. So I bought it. And he was right."

"Wow."

"Great book."

"Thank you."

"Fantastic book."

"Thank you."

"Possibly the best-written sports book I've ever read."

"Thank you."

But there was one bit I was curious about.

I explained that I'd interviewed Roger Federer in Basel a month before, and that the only time Federer had seemed uncomfortable was when Agassi's book had been mentioned.

PK: I asked if he had read the extracts and he said he hadn't, but that people had told him about it, and I found that strange. I said, "If that was me I'd have gone online straight away and read every word of what Andre Agassi had written." He said, "No, he wasn't that interested because it was just a book, and you can spend years on a book and write the story as perfect as you want, but I would rather hear him speak about it now." Does that surprise you?

AA: Emmm, I think there is power in books. My instinct would be that when you put something in black and white it is me speaking about it, you know, in a full context way. So I'm sort of conflicted with my reaction because I did speak about it, I spent 400 pages speaking about it. But I would embrace the opportunity to talk to him or anybody about it.

PK: Roger wasn't the only person in tennis who seemed uncomfortable with your revelations. Marat Safin said that you should return your prize money if you're feeling so bad about it. Martina Navratilova has you up there with Roger Clemens (the disgraced baseball star). And the one that kind of stuck-out was Rafael Nadal, who said: "Cheaters must be punished and if Agassi was a cheater during his career he should be punished." This is the question: Was Andre Agassi a cheat during his career?

AA: I cheated myself.

PK: In what way?

AA: I took a drug that destroys me . . . that doesn't hurt anybody else. It's not a performance enhancer. It's a performance inhibitor. It's a destructive drug that's impossible to play tennis on, which I never did.

PK: You say it's a performance inhibitor. Are you sure about that? Because I've taken amphetamines for sport and it enhanced my performance.

AA: Oh, this isn't amphetamines - well, it's a form of amphetamines - this is something you take and you literally don't sleep for 24 hours. It's violent. It would be a physical impossibility to compete on this. Now if the competition was for how long you can stay up then yeah, I would say it's a performance enhancer, but unfortunately (that's not what) tennis is about.

PK: I've written extensively on doping in sport and the passage in the book that makes me most uneasy is on page 200. The year is 1994, you have just become the first unseeded player since the '60s to win the US Open and now the goal is to become Number 1. This is the quote: "I cloister myself in Gil's (his personal trainer, Gil Reyes) gym and train with fury. I tell him about the goal, and he draws up a battle plan. First, he designs a course of study. He sets about collecting a master list of phone numbers and addresses for the world's most acclaimed sports doctors and nutritionists, and reaches out to all of them, turns them into his private consultants." Who were these acclaimed sports doctors? What was the nutrition? (He reaches for the salted almonds.)

AA: He has a network of people that work in the Olympic training institution in Colorado Springs, and a number of people that are responsible for writing the American sports medical journals . . . Let me put it this way, this is going to sound really strange, but the greatest advantage I had with Gil when I started with him is that he knew nothing about tennis and didn't look at it through the same lens that everybody else looked at it through. This was the day and age when people didn't believe in weight training and he looked at it and said, "Wait a second, if you make the muscles stronger you've made them more capable." Gil never stopped learning, it was his greatest thing. 'Gil water' (a drink Reyes prepared for him) was a hybrid of the right ratios between supplements and minerals and salt and carbohydrates and protein. He was a scientist about it. It's the way he approached his craft.

PK: What about steroids and EPO? How do you know you weren't taking any of that stuff?

AA: Because I got tested 150 times from WADA - 20 times a year out of competition. I mean the truth is that I love Gil like my father, we're family. Secondly, he would never do that to me, but the reason why you can know that's not the case is because of the extent the ATP goes to protect its integrity is vicious. It's tireless the efforts that my peers as well as our organising body have gone to to answer that question.

PK: Since 1999?

AA: Yeah.

PK: What about before 1999?

AA: Oh, before 1999 we were still on the cutting edge comparative to other sports in understanding that we need to implement a system that works. I shined a light on a flawed system that we abandoned, that we moved on and grew from.

PK: Pat Cash says: "Things were so lax when I was playing in the late '80s and '90s I was tested just once in all that time." So the question, given things were so lax is, why not take steroids? Why not take EPO? Why not avail of these products that were going to help you in this gladiatorial arena?

AA: Oh it would be a huge advantage, anything that's a sport . . . it would be a huge advantage.

PK: So the question is why not?

AA: Because it's cheating . . . I don't have the exact years of when we started to evolve but I came in in 1986 and the testing I think in any sport was basically non-existent. It was not even considered and tennis players looked like school teachers. I mean you didn't see guys out there that looked like Nadal or these athletes of today, and I don't know if it ever grabbed anybody's attention, but as sports started to change, as the business opportunities started to really become questionable, our sport took the necessary steps, and the leading steps, in governing its own integrity. So we have always been pushing to be ahead of anybody that cheats in our sport.

PK: Well, not always. The issue in your book that has stoked most debate is the response of the ATP when you tested positive for crystal meth. They did not want to know about it: 'This is not going to be a controversy.'

AA: Right.

PK: So how do I balance that with your positive for crystal meth?

AA: Are you familiar with WADA?

PK: Yes.

AA: Are you recently familiar with a case where somebody tested positive for cocaine?

PK: Yes, Richard Gasquet.

AA: There was a two-year mandatory (ban) but did you hear why they removed it? Did you see their quotes? "(He was) a man of integrity . . . (it was) a non-performance enhancing drug . . . a performance inhibitor . . . minute traces." This organisation is responsible for the Olympic Games (and they) concluded that maybe (Gasquet) has a problem. And maybe in this there should be some humanity. Crystal meth is a non-performance enhancing drug.

PK: I accept that, but I'm interested in the period before WADA came in. That's what people are wondering about now, and it's not just from outsiders and journalists, it's people within the game. This is a quote (from a column written by Cash) after the first extracts of your book were published: "I was not surprised that he (Agassi) confessed to taking drugs this week - though I was amazed that they were of the recreational variety. Suspicion among the other players had long been rife that he may have used some substances to help him become one of the fittest and strongest guys around, although there was never any proof."

AA: That's just not the case. I don't know what you want me to say to that. (I hand him a copy of Cash's column and continue reading.)

PK: "There were some dubious circumstances, none more than his early morning withdrawal from the defence of his title at the 2002 Australian Open citing a wrist injury. Back then I remember Australian Sports Drug Agency boss John Mendoza maintaining drugs were a major issue for the sport and claiming the ATP Tour was covering up positive results. I also recall Magnus Norman, a French Open finalist, writing in a book that was only ever printed in Swedish that there were suspicions about Agassi being one of the six names that never came to light after being found to have tested positive by the ATP. Agassi had been locked away for hours with the tour hierarchy in Melbourne and a knowing look appeared on many faces in the locker room."

AA: I don't have any comments on that kind of speculation. It's absurd to me.

PK: Absurd?

AA: It's absurd to me. I know everything I've been through in my life.

PK: That was the only aspect of the book that left me uneasy. I mean, you say the sport is clean but . . .

AA: Oh fuck!

PK: "I'm sorry, I don't mean to drag this out but you're the only player who has . . .

AA: No, go ahead, you've got work to do.

PK: Why does that upset you? Tell me why I've upset you?

AA: I'm not upset. I'm going to answer your questions and treat them fairly.

PK: Okay, well, as I say, that was the only area of the book that left me dissatisfied. I thought: 'I wish he had addressed the issue of doping in tennis.'

AA: But I can only speak to what I know. I'm charged with that duty in this book, which is why I can't speak to speculation - because that's all it is. And it's irresponsible.

PK: So the use of performance enhancing drugs was never a temptation for you during your career at any stage?

AA: At any stage.

PK: You trusted Gil implicitly with what he was giving you.

AA: And I had everything he was giving me. It wasn't a secret what he was giving me. It was combinations of very important things that a person needs . . . You're more than welcome to take your investigation and come to Vegas to see some of it.

I never made it to Vegas, and the interview - one of the more interesting I've conducted - was never published, perhaps because my employers at the time - the 'Champions of Journalism' who took on Lance Armstrong - applied different standards to tennis. Or perhaps, as they insisted, it just wasn't very good.

I was reminded of Andre again last week when The Times published a great photo of Maria and her friends from Nike, at a special event in New York before the US Open last year. He's sitting on the back of the car with Roger and Rafael, Pistol Pete and Big Mac, united with them in Swoosh, just a big happy family.

Sunday Indo Sport