Grand Slam title winners are alleged to be among the reported players

Wimbledon was dragged into a new tennis match-fixing scandal when secret files suggested three matches may have been thrown there in recent years.

Leaked files from anti-corruption investigators allege that the sport's authorities have covered up the extent of the problem and allowed some of the main suspects to continue playing.

The documents have been passed by whistleblowers to Buzzfeed News and the BBC, who have decided not to reveal the players' names. But from a group of 16 who were implicated when the scourge was at its height around eight years ago, some are still on the circuit.

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Matches at Wimbledon are among those caught up in a new tennis match-fixing scandal

Secret files suggest that three matches have may have been fixed on the SW19 courts in recent years

TENNIS MATCH-FIXING ALLEGATIONS - THE KEY NUMBERS 16 - core group of players who are claimed to have repeatedly been reported for losing games when highly suspicious bets have been placed against them. 26,000 - matches that are alleged to have been examined in a report handed to tennis' governing bodies that was not acted upon. £35,000 - the figure said to be offered per fix to players by corrupt gamblers. 70 - players names reported to appear on nine lists of suspected fixers flagged up to tennis authorities. Advertisement

It is alleged that more than half of them were in the starting field for the Australian Open, which began on Monday.

The central allegation is that an examination of 26,000 matches given to the sport's governing bodies in 2007 provided enough evidence to tackle players, but was not acted upon.

Three matches at Wimbledon are said to be in the files, though it is not clear when they took place. The Tennis Integrity Unit, set up to police the sport in 2007, said they had a zero-tolerance approach to betting-related corruption.

Their job was to look into suspicious betting activity after a game involving Nikolay Davydenko and Martin Vassallo Arguello. The two players were cleared of violating any rules but the investigation developed into a much wider inquiry looking into a web of gamblers linked to top-level players.

It was claimed that the investigation revealed:

Winners of singles and doubles titles at Grand Slam tournaments are among the core group of 16 players who have repeatedly been reported for losing games when highly suspicious bets have been placed against them.

One top-50 player competing in the Australian Open this week is suspected of repeatedly fixing his first set.

Players are being targeted in hotel rooms at major tournaments and offered upwards of £35,000 per fix by corrupt gamblers.

Gambling syndicates in Russia and Italy made hundreds of thousands of pounds placing highly suspicious bets on matches — including at Wimbledon and the French Open.

The names of more than 70 players appear on nine lists of suspected fixers who have been flagged up to the tennis authorities over the past decade without being sanctioned.

It is not clear when the matches that are said to have been fixed at Wimbledon had taken place

Nikolay Davydenko (pictured) and Martin Vassallo Arguello were cleared of violating any rules over a match between them but the investigation developed into a much wider inquiry looking into a web of gamblers

THE ONE WHO GOT CAUGHT Austrian Daniel Kollerer remains the most high-ranking tennis player banned for match-fixing. Kollerer, who reached a career-high 55th in 2009, was found guilty in 2011 of three violations of anti-corruption rules, including 'contriving or attempting to contrive the outcome of an event.' The violations occurred between October 2009 and July 2010. Kollerer appealed his life ban but it was upheld by the Court of Arbitration for Sport. Advertisement

In a confidential report for the tennis authorities in 2007, the inquiry team said 28 players involved in these games should be investigated but the findings were never followed up.

Tennis introduced a new anti-corruption code in 2009 but after taking legal advice were told previous corruption offences could not be pursued.

'As a result, no new investigations into any of the players who were mentioned in the 2007 report were opened,' said a TIU spokesman.

In subsequent years there were repeated alerts sent to the TIU about a third of these players. None of them was disciplined by the TIU.

In 2011, Austrian Daniel Kollerer, then ranked 385th in the world, was banned for life for match-fixing and was fined $100,000 (£70,000) by the TIU, but he remains the most high-profile player to be convicted.

'The evidence was really strong. There appeared to be a really good chance to nip it in the bud and get a strong deterrent out there to root out the bad apples. They could have got rid of a network of players that would have almost completely cleared the sport up. We gave them everything tied up with a nice pink bow on top and they took no action at all.'

ATP president Chris Kermode admitted he was aware of match-fixing but said it is at a 'small level'

Tennis Integrity Unit documents have been passed by whistleblowers to Buzzfeed News and the BBC

HOW IT WORKS BuzzFeed have explained exactly how they came to their conclusions. A code, which you can read by clicking HERE, was used to identify suspicious matches by analysing betting patterns against player performance in more than 26,000 matches from 2009 and mid-September 2015. Advertisement

In an interview with the BBC on Sunday night, ATP president Chris Kermode admitted he was aware of match-fixing within tennis but insisted it is at an 'incredibly small level'. He added: 'It is simply not true that we are sitting on evidence.

'What happens is information and intelligence are given to the TIU and they have to turn that into evidence. There is a big difference between information and evidence.

'I can assure you that tennis is not treating this lightly. The idea that tennis is not acting appropriately is ludicrous.'