Call of Duty World at War looks increasingly likely to be the top selling game this Christmas as the game holds its fourth consecutive week atop the UK all-format charts.

Treyarch’s successor to Infinity Ward’s Modern Warfare holds the top spot despite a second consecutive sales drop for all formats (this week down 15 percent, last week 30 percent). Activision’s flagship title also resists the rising popularity of Mario Kart Wii, which has seen a 15 percent sales boost (enough to push it to second from fourth) in line with Nintendo’s recent assault on UK TV advertising slots.

Right now it looks likely that nothing will stop World at War – of which you can read Edge’s verdict on here – from replicating the success of last year’s UK Christmas number one, Call of Duty 4: Modern Warfare. Last Month Paddy Power had World at War as the 5-2 favorite for taking the Christmas number one spot; at the time of writing those odds have shortened to 4-6.

World at War has now sold 1m units in the UK alone, a landmark which took Modern Warfare 8 weeks to reach.

Remaining in third this week is FIFA 09, a game which – aside from one week in mid-November – has remained in the top three of the UK all format charts since early October. EA’s other key title right now, Need for Speed: Undercover, slips from second to fifth after dropping 21 percent in sales.

Nintendo’s Wii Series/Touch! Generations self-selling synergy continues to grip the UK market, with Brain Training climbing to fourth, Wii Fit jumping from twelfth to eighth following a 43 percent sales boost, and Wii Play sales climbing 5 percent but dropping one place to ninth to allow Wii Fit to shoot past.

Nintendo’s Animal Crossing: Let’s Go to the City could only limp into the charts at number 26, a sales performance equal to the latest Prince of Persia for 360 and PS3, which dropped in at number thirty. Both these games were released on Friday, and next week’s charts will give the games’ sales rates a clearer picture. The other entrant in last week’s big releases, GTA IV for the PC, generates a 160 percent retail boost and takes the title from 40 to 22.

Another game which enjoyed a climb in sales was Tomb Raider: Underworld – climbing up to sixth – as well as Fallout 3, which takes a 60 percent surge after Gamestation slashed its price to £20. This week the retailer is trying to shift both 360 and PS3 versions of Soul Calibur 4 at roughly the same price, so expect to see a comparable sales jump next week.

All Format top-ten provided by Chart Track follows:

1. Call of Duty: World at War
2. Mario Kart Wii
3. FIFA 09
4. Brain Training
5. Need for Speed: Undercover
6. Tomb Raider Underworld
7. Fallout 3
8. Wii Fit
9. Wii Play
10. Guitar Hero World Tour

Last Week.
Chart History.