More than a third of all the music CDs sold last year were pirate copies, generating $4.6bn for organised criminal gangs and bootleggers, according to the trade association representing the world's largest music companies.

The International Federation for the Music Industry (IFPI) on Thursday accused governments and law enforcement agencies in several countries of failing to curb illegal music sales exacerbating a 30 per cent decline in industry revenues over the past four years.