Spending the day as a guest of Harry Findlay in his box at Royal Ascot might be construed as sleeping with the enemy. Tennis has invested copious time and money on an exhaustive review into its integrity and Findlay, who has probably risked more on the sport than anyone past or present, does not think much of any of it. “The police don't know anything about gambling, they [the tennis authorities] might as well have appointed a gynaecologist to look at it,” he said. “If they want to know about gambling, talk to gamblers, talk to me. I'm a legend.”

And so he is. Findlay has won and lost more wagering on tennis than Roger Federer, Rafael Nadal and Maria Sharapova have earned in prizemoney in total. “That's not being flash, that's just the way it is,” he said. “I love the Fed, he's won me more millions than anyone, he's changed my life.”

The 46-year-old left school at 16 to clean out the local greyhound kennels in Buckinghamshire for £18 a week. His life went in its present direction 20 years ago with an £80 treble linking a racehorse, Holland in the European Championship and Stefan Edberg at Wimbledon. He won £11,000 and will probably gamble five times that much each day this week at Ascot.

Which is why Findlay is in a rage, which is not the best of moods for a professional gambler, who constantly needs to have his wits about him. “It's time people like me sat down with Etienne de Villiers [the president of the ATP, the men's governing body] and told him he does not have an inherent problem,” he said. “There's not been a single bent match in grand-slam tennis in the past 30 years and I know, because if there had been, I'd be destitute. I've tried to get to him but I keep being swept under the carpet.

“I know there were problems with the [Nikolay] Davydenko-[Martin] Vassallo Arguello match in Poland last August and the naivety of the odds were so laughable [Davydenko was the equivalent of 5-1 against when he ought to have been 5-1 on] something was wrong. But you can't start blaming Davydenko, you just can't.”

Betfair, the world's leading online betting exchange, with whom the sport has a memorandum of understanding, voided all bets. An investigation into the match remains unresolved ten months later; Davydenko and Vassallo Arguello are in a state of limbo. “It's obscene what's been allowed to happen to these players,” Findlay said. “We are dealing with a sport and sportsmen who are more straight than most people in business and if it continues to be tarnished, it's unfair. I've heard about all these supposedly suspect matches but these are in satellite events where no money changes hands. ”

Findlay's three great sporting loves are horse and dog racing - he is joint owner of Denman, the Cheltenham Gold Cup winner - tennis and darts. His newest equine purchase is to be named Pearl of Manacor in honour of Rafael Nadal. “No other sport has made me as much money as tennis and it's getting a lot harder now so I don't mind letting some of my secrets out,” he said. “The biggest financial reward is the switch from clay to grass and the combination of tournaments coming too close to each other.”

His recall of matches is uncanny. “I had [Paul] Haarhuis to beat [Fernando] Vicente on grass in 1999, I bet ten [thousand] to win one; the opposite would be the case on clay,” he said. “And that is why what Nadal did at Queen's last week was extraordinary. I had a really good crack at [Ivo] Karlovic against Nadal in the quarters. I had six figures on [Novak] Djokovic in the semis, I put more on when he was 2-0 in the first set and I thought this is it, we're going to get masses today, but did we f***. Nadal is a monster.

“Do you think I'd be nuts enough to put money like this on if tennis was bent? It's so straight it's unbelievable.

“I cottoned on to Federer very early, the day he played Xavier Malisse on Court No2 at Wimbledon [in 2001]. It's luck as well, not just judgment. He beat [Pete] Sampras in the fourth round - I backed him at 4-1 - but the next day [Tim] Henman beat him in the quarter-final. Next year he got knocked out in the first round, by Mario Ancic, so the bookmakers thought he'd gone backwards. The following year he got knocked out in the first round in Paris by Luis Horna and that's when I knew he was going to win Wimbledon, because he would have the whole two weeks off before Halle. He was 10-1 and I made him about 2-1. It was the all-time coup.”

Net gains for a "genius"

§ “Roger Federer, Rafael Nadal and Novak Djokovic are the best I’ve ever seen and I can tell you that through my pocket - they are favourites on every surface, even the ones that aren’t their best and we’ve never had that in tennis. Having said that, Andy Roddick is a decent each-way chance at Wimbledon.”

§“I used to love the ladies. I had my biggest bet ever then, my biggest bet ever of £70,000 on Steffi Graf to beat Monica Seles in the 1992 Wimbledon final. It was too close to call at the bookies, evens Steffi and evens Monica but anyone who thought that Monica Seles could beat Steffi on grass knows f*** all about tennis.”

§ “This year at the French, Nadal was 100,000 to win 1,000 in the first three rounds, then 100,000 to win 2,000 later on whereas three years ago it was 100,000 to win 12,000, or 14,000 or 15,000. That’s how you appreciate how straight the sport is, it’s getting harder for me to win and I’m a genius.”