As he prepares to depart the ICC, Alex Marshall, the head of global cricket's anti-corruption unit (ACU), has warned that "badly run" domestic T20 leagues "at lower level" remain a "threat" to the game with corruptors looking to use them as an entry point. Marshall, 63, has decided to retire from the ICC job this November, ending a seven-year term, which started in 2017 as general manager of the ICC's integrity unit, which includes the security and anti-doping units apart from the ACU.

Marshall, a former senior policeman in the UK, recently communicated his decision to the ICC, saying he wanted to spend more time with his family, including parents and grandchildren in England. Marshall, who replaced YP Singh, was the fourth ACU head and was shortlisted by Sir Ronnie Flanagan, the independent chairman of the anti-corruption watchdog.

Marshall said that while the malaise of corruption will continue to shadow cricket, he was "proud" that during his stint the ACU had been successful in helping players be more forthcoming about approaches from corrupters. "I am proud of the significant increase in trust from players who now report approaches to us frequently whereas there was a time when they lacked confidence in confidentiality and the action that will be taken," Marshall told ESPNcricinfo on Friday. "They have now seen corruptors being disrupted, named, banned when they get involved in cricket. And the education we now do with players shows them who the corruptors are, what their methods are, so everyone is much better equipped and protected to keep corruption away from the game."

Marshall said he was happy with the progress in Sri Lanka, where he says there are now stronger guardrails to ward off corrupt elements. "Sri Lanka turned out to be a good news story because there were serious issues which were addressed locally and with ICC," he said. "Now with the legislation and stronger measures Sri Lanka is in a much better place to keep the corruptors away."

Two other former international captains, Bangladesh's Shakib Al Hasan and Zimbabwe's Heath Streak, who passed away last September, were charged by Marshall's ACU for wrongdoing. Both players accepted their offence. In 2019, the ACU sanctioned Shakib across the three international formats for failing to report "not one but three" approaches made by alleged corruptor Deepak Aggarwal to engage in corrupt conduct in two tournaments in 2018: an ODI tri-series in Zimbabwe and an IPL match the same year when the Bangladesh player featured for Sunrisers Hyderabad.

As he prepares to leave his ICC job, Marshall has a word of caution for those administering, playing and governing cricket: that corrupt elements continue to wander around, waiting for any opportunity to enter the system. And one of those routes, Marshall stressed, was "badly" managed T20 franchise leagues, which are outside the ambit of the ICC ACU and are instead monitored by the member country boards.

"I am confident that the cricket you watch is safe and clean," Marshall said. "But I am also absolutely sure that corruptors are constantly looking for a route into the game, particularly in badly-run lower-level franchise leagues. The threat to the game is corruptors won't go away while there is always money to be made and they will look for weakness in the system to get in."