EAST Lancashire's Diana Vickers is set to be number one this weekend as Hero, the new track by all the X Factor finalists, is expected to become the fastest-selling single of 2008.

The single has been recorded for Help for Heroes, a charity that provides support for wounded servicemen and women.

The cover of Mariah Carey's hit is currently the best-selling single at HMV, and at the top of Play.Com's download chart and the iTunes download top 100.

Online retailer Amazon said it had sold out of the track in just a few hours.

Hero hit the shops today and has been available to download since Sunday.

HMV spokesman Gennaro Castaldo said: "Single releases tend not to be such a big event these days, but this one is definitely bucking the trend.

"We predict it will become the fastest-selling single of this year."