Tennis has been engulfed by a “tsunami” of corruption at the lower levels of the game involving “serious and substantial” match-fixing, an independent task force warned on Wednesday.

The scale of the problem was set out by Adam Lewis QC, the author of Independent Review of Integrity in Tennis, who said “tennis is responsible for more suspicious betting than any other sport”. A survey of 3,200 players at all levels of the professional game found that 14.5% had first-hand knowledge of match-fixing – 464 players in total.

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The interim review, which was finally published after a 27-month process that cost nearly £20m, proposed a number of controversial solutions to tackle the problem, including banning betting companies from sponsoring tennis and gambling on lower-level matches. But it insisted the evidence did not reveal a “widespread problem” in elite professional tennis or a cover-up by the game’s authorities.

According to Lewis, many of the problems dated back to the International Tennis Federation’s decision in 2012 to sign a $70m deal with the data company Sportradar to distribute live scores from small and intermediate tournaments around the globe. It meant bookmakers could provide odds on those matches, particularly on the lucrative in-play market – and unscrupulous gamblers had a prime opportunity which they could exploit.

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The report noted: “The panel has seen little empirical evidence that betting was widespread on the lowest levels of ITF tournaments before the deal in 2012. But in 2013, the year after the first ITF-Sportradar contract, 40,000 matches at ITF Men’s Futures and Women’s 15k and 25k events were made available to the betting market. By 2016 that number had increased to over 60,000.”

Because the Futures events offer such poor prize money, the report found that only 336 men and 253 women were able to break even – and that was before accounting for coaching costs. It meant that many players were vulnerable to being manipulated by fixers. “The nature of the game lends itself to manipulation for betting purposes,” the report added. “The player incentive structure creates a fertile breeding ground for breaches of integrity. Today tennis faces a serious integrity problem.”

Umpires were sometimes involved, too. As the Guardian revealed in 2016, under the terms of the Sportradar deal, umpires were asked to immediately update the scoreboard after each point using their official IBM tablets. But some umpires deliberately delayed updating the scores for up to 60 seconds – allowing gamblers to place bets knowing what was going to happen next.

That problem has now been tackled but the report admitted there was “no simple solution or panacea” to deal with the many other outstanding issues. It suggested discontinuing the sale of official live scoring data at lower levels of the game would help.

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However, Sportradar responded angrily to this proposal calling it “unrealistic and potentially unlawful”. In a statement it warned: “Prohibition simply doesn’t work. Prohibiting data partnerships will not stop betting, live or otherwise, on these matches nor will it remove corruption risk at this level. Pre-match betting will remain available and the risk of data fraud and ghost matches will increase. This will almost certainly encourage black-market activity.”

The ITF was criticised in the report for “at times insufficient” investigations around grand slams and the ATP for not doing more in following up on a report by Richard Ings’s original anti-corruption code in 2005. Tennis authorities say they plan to implement the findings of the final report, which is scheduled to be published in the autumn.