Wii Fit has successfully and thoroughly staked its claim at the top of the Charts. The 'game' is, according to Chart-Track, the "6th fastest selling UK debut ever", having been beaten only by products in the GTA, Halo and Gran Turismo series.

Chart-Track also tells us that Wii Fit, with its Balance Board peripheral, was bought by one in ten Wii owners in the UK in its first two days of release. The game stacked up an estimated £16.3m in sales, making it (again, according to Chart-Track) “the 3rd largest launch in terms of value for a video gaming product”. It comes in behind Grand Theft Auto: San Andreas (£24.2m in week 44 of 2004) and Halo 3 (£16.9m in week 39 last year).

Nintendo has also managed to top the success of Mario Kart Wii two weeks ago. Wii Fit has supplanted it as the company's fastest selling UK release ever. In fact, half the Wii software sold this week comprised copies of Wii Fit, with 79% of all Wii software sold having been sold by either Nintendo or SEGA.

You cans see SPOnG's review of Wii Fit here.

Number 2 is the spot Mario Kart Wii has been bumped down to after a 62% drop-off in sales. Right behind it is SEGA's Mario & Sonic at the Olympic Games, down from Number 2 last week.

Sony's GT5 Prologue and Konami's Pro Evolution Soccer 2008 both slip one place, landing them at Numbers 4 and 5 respectively. Brain Training is the only Top 10 game to make any ground, climbing up from Number 9 to Number 8.

Promotion at retail means a few titles climb the Charts this week. SEGA's Sonic & The Secret Rings makes its way from Number 25 to Number 17, Ubisoft's Rayman Raving Rabbids 2 is up from Number 22 to 19, THQ's WWE Smackdown vs Raw 2008 is up from Number 34 to 21 and Halo 3 makes a Top 40 reappearance at Number 31.

The only other new entry this week is Sony's Singstar Summer Party, which hits the Charts at Number 30.

Next week, there will be a little game called GTA IV in the Charts following its release today. If it isn't at Number 1 SPOnG will eat every piece of headgear it can find in the underwater castle, including Andy SPOnG's comedy clown flat cap. The only other publisher that is daring to release a game of note is SEGA with Iron Man.

You can see the Top 10 below (last week's positions are bracketed). For the Charts in full, head this way.

(NE) 1 Wii Fit - Nintendo
(1) 2 Mario Kart Wii - Nintendo
(2) 3 Mario and Sonic At The Olympic Games - SEGA
(3) 4 Gran Turismo 5: Prologue - SCEE
(4) 5 Pro Evolution Soccer 2008 - Konami
(7) 6 Call of Duty 4: Modern Warfare - Activision
(5) 7 Sega Superstars Tennis - SEGA
(9) 8 Dr Kawashima's Brain Training - Nintendo
(8) 9 UEFA Euro 2008 Austria-Switzerland - EA Sports
(6) 10 Tom Clancy's Rainbow Six: Vegas 2 - Ubisoft