An honest but serious mistake was the so-called ghost goal Atkinson awarded in the 2012 FA Cup semi-final Chelsea vs Spurs. Leading 1-0 Chelsea player Mata took a shot that was cleared before the goalline. Since Atkinson stood far off most people assumed he just guessed what happened and gave the goal. Chelsea went on to win 5-1 so it wasn't that pivotal.
From our reporter: Karl Muller