Winehouse's second and final album Back To Black took the runner-up position with total sales upwards of 3.56 million since its release in 2006.
James Blunt's debut album Back To Bedlam is close behind in third-place. The 2004 release spent 10 weeks at the Official Albums Chart summit, and has now sold 3.31 million units. Rounding out the Top 5 are debut albums from Leona Lewis (Spirit with 3.13 million U.K. sales) and Dido (No Angel with 3.08 million sales).
The list is a testament to the pulling power of domestic repertoire. Eight of the 10 top albums are homegrown artists, the notable exceptions being Canadian crooner Michael Buble's Crazy Love, which is at No. 7, and U.S. pop star Lady Gaga's the Fame at No. 9.
Robbie Williams and his sometime boyband Take That tie for the most entries in the Top 50 with four apiece, while Coldplay (3), Dido (2), Ed Sheeran (2), Michael Buble (2) and Rihanna (2) also land multiple berths.
Adele's Next Album and World Tour Confirmed? 'No Truth' in New Rumor
Just two albums released prior to 2000 have made list: David Gray's 8th placed White Ladder (released in 1998) and the 19th placed ABBA Gold – Greatest Hits (released in 1992).
The OCC also notes only 39 albums have passed the 2 million U.K. sales threshold since the turn of the century, the latest being Ed Sheeran's X, which achieved the feat in the past week.
There's still no firm release date, or even a title, for Adele's third studio album. But there's a good chance it'll have a country sound. Kelly Clarkson recently let slip in an interview that she "heard [Adele] is doing something more country influenced with this next record."
10 Biggest Selling Artist Albums of the Millennium in the U.K.
1. Adele, "21" (Xl Recordings)
2. Amy Winehouse, "Back To Black" (Island)
3. James Blunt, "Back To Bedlam" (Atlantic)
4. Leona Lewis, "Spirit" (Syco Music)
5. Dido, "No Angel" (Arista)
6. Beatles, "1"(Apple Corps)
7. Michael Buble, "Crazy Love" (Reprise)
8. David Gray, "White Ladder" (East West)
9. Lady Gaga, "The Fame" (Interscope)
10. Coldplay, "A Rush Of Blood To The Head (Parlophone)