A tit-for-tat legal battle broke out between Apple and Creative this week over technology used in the companies’ rival digital music players.

Singapore’s Creative kicked off the action, filing a suit against Apple claiming the iPod maker, which with a 77 per cent share dominates the US market for MP3 players, had infringed one its so-called “Zen” patent relating to hierarchical categorization of music - menus used to choose and play music - and sought to stop sales of some models of Apple’s iconic hand-held digital player.