1. A gaming machine having a display means and a game control means arranged to control images displayed on the display means, the game control means being arranged to play a game wherein random events are caused to be displayed on the display means and. if a predefined winning event results, the machine awards a prize, the gaming machine being characterised in that if the predefined result includes a trigger condition which results in an initial series of free games awarded to a player and, during the initial series of free games, another trigger condition arises. a subsequent series of free games, including a bonus feature, is awarded and implemented immediately during the existence of the initial series of free games with the bonus feature applicable to said subsequent series of free games being applied to the remaining games of the initial series of free games as well as to the games of the subsequent series of free games.