In September 2017, Marshall retired from policing to work for the International Cricket Council (ICC), as general manager of its Anti-Corruption Unit.
[1][2] Marshall is currently the General Manager of the ICC Integrity Unit which includes, Anti-Corruption, Anti-Doping, Security and Safeguarding.
Marshall was a Detective Chief Inspector in the Metropolitan Police, Anti-Corruption Command.
During this time he also worked as a consultant for the Home Office on bureaucracy in frontline policing.
[3][4][5] Marshall received the Commander of the Most Excellent Order of the British Empire in the Queen's 2018 Birthday Honours.