Heaven only knows where they got this figure, but market researcher TNS Technology reckons the emerging unlimited mobile music services like Nokia’s (NYSE: NOK) Comes With Music an SonyEricsson’s (NSDQ: ERIC) PlayNow Plus could see UK users download 2.1 billion tracks per year.

To put that in context - last year, people around the world bought only 1.7 billion tracks on both online and mobile. But the move from individual track purchases to the all-you-can-eat “celestial jukebox” could shift the market significantly, TNS says…

From 1,000 people it interviewed, a quarter expressed an interest; they said they would download an average 64 tracks a month, though those 16-to-24 would gobble twice that. Some 45 percent of them would buy fewer CDs and 47 percent fewer downloads, while 38 percent would use illegal P2P less, Guardian.co.uk reports.

All this is a far cry from accepted wisdom about the mobile music business, which actually barely qualifies as a “business” at all. Aready packing MP3 players of their own, two third of people are not interested in mobile music, an April Jupiter report found. At our EconMusic conference last week, SonyBMG digital VP Ian Henderson said both the mobile music segment and his label’s income from it were in decline. Pay-monthly unlimited access and, in Nokia’s case, basically free access may help bump up the market - but it’s still likely to come down to that ‘ol chestnut of getting the user interface right.

• Most Adults Don’t Want Mobile Music - Research
• @ EconMusic: Mobile Music: A Panacea In Decline?