Secret files which allegedly contain evidence of widespread match fixing at the top levels of world tennis, including at Wimbledon, have been revealed.

An investigation by the BBC and BuzzFeed News alleges that dozens of top world players are suspected to have been involved in match fixing, with some reported to tennis officials over suspicions that they deliberately lost matches.

All of these reported players, some of whom are alleged to be Grand Slam title winners, were allowed to continue playing.

The news organisations were passed the documents by anonymous whistleblowers inside the world of tennis. These documents included the findings of a 2007 investigation by the Association of Tennis Professionals (ATP), which was set up to look into claims of match fixing and suspicious gambling.

The investigation found that gambling syndicates in Russia, Northern Italy and Sicily had made hundreds of thousands of pounds betting on matches that were believed to have been fixed, three of which were at Wimbledon.

A follow-up enquiry suggested 28 players involved in these games should be investigated, but their recommendations were never followed up.

A new anti-corruption code was introduced to the sport in 2009, but due to legal issues, suspected corruption offences committed before its introduction could not be pursued.

The BBC and BuzzFeed news have not named the players involved in the allegations, because without access to their personal records, it would be impossible to determine whether they took part in match fixing.

However, they did claim that players are allegedly being targeted in hotels at major tournaments and offered upwards of $50,000 (£35,000) to throw points during matches.

The investigation alleges that a core of 16 players have repeatedly been reported for losing games when suspicious bets are made against them, but also says more than 70 players have reportedly been flagged up to authorities in the last decade without being investigated.

Prime Minister David Cameron addressed the allegations on Monday morning and called for an immediate and thorough investigation into the match-fixing claims, and admitted that the sport now needs to rebuild its reputation much like other sports such as football and athletics are currently attempting to do.