Chart-Track report that Call of Duty: Modern Warfare 2 is now the third highest selling title of all time in the UK. Thanks to the first week sales of 1.78M released by Chart-Track, along with subsequent weekly percentage change reports we know that Modern Warfare 2 was at 2.97M through Jan 09. This number is the estimated total for 100% of the market, actual tracked sales from Chart-Track which covers around 90% of the UK market should be 2.67M.
Dr.Kawashima's Brain Training currently holds the number one spot having passed 3M and GTA: San Andreas in the first half of 2009, again, this number is for 100% of the market. With the title still charting it should have added a few hundred thousand since then.
Current second position holder is Grand Theft Auto: San Andreas, ELSPA accidentally posted the PS2 version's LTD of 2,355,328 with the week 10 2009 charts, as it was still selling ~1K/week it should be around 2.4M by now. The Xbox version is between 200,000 and 300,000, with the PC version between 100,000 and 200,000 according to their ELSPA Sales Awards. The ELSPA numbers aren't extrapolated for 100% of the market though. GTA: San Andreas launched on PS2 in November 2004 when Chart-Track covered 85% of the market, before they increased to 90% coverage in January 2005, which complicates extrapolating to 100% of the market as sales are split over two different percentage coverages. For simplicities' sake I've used the middle figure of 87.5%. This puts the tracked sales at around 2.8M, or around an estimated 3.2M for 100% of the market.
Below shows that MW2 should soon take second place from GTA: SA, but first place should take a while longer, if at all. Maybe if Chart-Track are feeling generous they'll mention how much the other two have sold when this occurs.
All Time UK Top 3: 90% / 100%
01. [NDS] Dr.Kawashima's Brain Training: 2,800,000+ / 3,100,000+
02. [ALL] Grand Theft Auto: San Andreas: ~2,800,000 / ~3,200,000
03. [ALL] Call of Duty: Modern Warfare 2: 2,670,000 / 2,970,000
Call of Duty: Modern Warfare 2 weekly sales (100%):
WK46 09: ---% = 1,780,000
WK47 09: -86% = 249,000
WK48 09: -32% = 169,000
WK49 09: -07% = 158,000
WK50 09: -11% = 140,000
WK51 09: +03% = 144,000
WK52 09: +17% = 169,000
WK53 09: -41% = 100,000
WK01 10: -41% = 59,000
WK02 10: -17% = 49,000
WK03 10: -10% = 44,000
WK04 10: -03% = 43,000
WK05 10: -12% = 38,000
Grand Theft Auto: San Andreas sales (85%-90%):
[PS2] 2,355,328 (WK10 09)