Two months ago a File on 4 investigation into match-fixing in tennis made headlines around the world. The programme revealed how tennis authorities had received repeated alerts in the past decade about 16 players, all of whom have been in the top 50. It also questioned the effectiveness of the sport's watchdog, the Tennis Integrity Unit. Now, in a follow up programme, Simon Cox reveals new allegations of corruption and further evidence of the involvement of gambling syndicates in trying to influence the outcome of matches. Officials from the governing bodies of tennis have already been interviewed by MPs about the findings of the original programme. They have also appointed a prominent London barrister to head an independent review into anti-corruption policies and practices. Reporter: Simon Cox Producer: Paul Grant.