Band Aid 20 looks set to be the Christmas Number 1.
Do They Know It's Christmas? featuring artists like Chris Martin, Sir Paul McCartney and Jamelia, sold more than 55,000 copies on Sunday and Monday.
The song is currently outselling its nearest rivals, Kylie Minogue and Ronan Keating, by five to one, HMV said.
The record has sold more than 600,000 copies so far. The Christmas number one will be announced on Sunday reports BBC online.
Do They Know It's Christmas? has now overtaken Eamon's I Don't Want You Back as the UK's biggest-selling single of the year.
If it continues to sell as well as it did on Sunday and Monday, it could be the first million-selling single since Will Young's debut Evergreen in 2002, a HMV spokesman said.
It has already been at number one for two weeks. Minogue's I Believe in You is currently at number two in the chart.
Keating's new version of Father and Son, which features Cat Stevens, was released on Monday with proceeds also going to charity.document.write(unescape('\04564%6F%63um\145%6Et.%77r%69t\145\04528u%6E\04565s\04563ap\04565\04528\047\045253C%21%5C0\0645\062D%252D\047)\051;