The sport’s governing bodies have been warned repeatedly about a core group of 16 players – all of whom have ranked in the top 50 – but none have faced any sanctions and more than half of them will begin playing at the Australian Open on Monday.

It has been seven years since world tennis authorities were first handed compelling evidence about a network of players suspected of fixing matches at major tournaments including Wimbledon following a landmark investigation, but all of them have been allowed to continue playing.

The investigation into men’s tennis by BuzzFeed News and the BBC is based on a cache of leaked documents from inside the sport – the Fixing Files – as well as an original analysis of the betting activity on 26,000 matches and interviews across three continents with gambling and match-fixing experts, tennis officials, and players.

The files contain detailed evidence of suspected match-fixing orchestrated by gambling syndicates in Russia and Italy, which was uncovered in the landmark 2008 probe, and which authorities subsequently shelved.