Secret files exposing evidence of widespread suspected match fixing at the top level of world tennis can be revealed by the BBC and BuzzFeed News.

Over the last decade 16 players who have ranked in the top 50 have been repeatedly flagged to the Tennis Integrity Unit over suspicions they have thrown matches, including at Wimbledon.

All of the players, including several Grand Slam doubles winners, were allowed to continue competing.

Simon Cox reports.