The Military Wives' single Wherever You Are is the fastest selling single for six years, almost guaranteeing them the top spot.
Gareth Malone's choir sold more singles in two days than the X Factor winners sold last week following their victory in the UK talent competition.
Wherever You Are has so far shifted 242,000 copies, outselling Little Mix by a ratio of 6:1.
The girl band only achieved 210,000 sales for their single, the Damien Rice cover Cannonball, last week, considerably lower than previous X Factor winners.