Despite being chairman of the Players' Union (the Professional Dart Players Association - PDPA), Manley was often the subject of controversy with fellow players. Most notably Taylor in the aforementioned incident, and also in the 2006 PDC World Darts Championship. During that tournament, Manley was accused of gamesmanship against Dennis Smith and in a later round against Taylor's protégé, Adrian Lewis. Manley muttered words to his opponent, resulting in Lewis leaving the stage in anger. Despite serving as Mardle's best man at his wedding Manley also had a notable spat with the former PDC professional player Wayne Mardle. Mardle accused Manley of being a cheat in his autobiography. Manley has also had notable spats with the likes of Roland Scholten, John Lowe, Rod Harrington, Dave Jowett and Wynand Havenga.