In 3rd place was Harry Potter & The Deathly Hallows - Part 1, the movie not the game, followed by EA Sports' FIFA 12. Battlefield 3 came 11th with 1,186,895 units cleared.
Of course the music industry cheats because their digital sales are accounted for while online game purchases still aren't so Call of Duty: Modern Warfare 3 likely deserves the crown.
The Top 40 sellers in UK entertainment sold 48.2m units in 2011 which is up 1.5 percent on 2010.
See below for the full chart listing, courtesy of the ERA.