UK Chart: San Andreas back on top, as NFSU2 beats Half-Life 2 to No.2

Rockstar's Grand Theft Auto: San Andreas has reclaimed the top spot in the UK charts this week, while Need For Speed Underground 2 has outsold Half-Life 2 to take the number two position.

Following an incredibly strong first week, Xbox-exclusive title Halo 2 has dropped three places in its second week on sale, coming in at number four in this week's chart, and leaving the top spot clear for Rockstar's PS2 behemoth once more.

Vivendi meanwhile will no doubt be disappointed that the hugely anticipated Half-Life 2 has only managed to chart at number three in the ranking, although that still makes it into the third fastest selling PC game ever in the UK, behind Championship Manager 4 and The Sims 2.

Of course, the question in many people's minds will be how many sales the title has racked up on the Steam online distribution service set up by developer Valve, which allows gamers to buy directly over the Internet and bypasses both the retail channels and Vivendi itself in the value chain.

These sales would not, of course, be counted in the Chart-Track figures for the title - so the true scale of Half-Life 2's success won't be known until Valve chooses to release figures for sales over Steam.

Electronic Arts' Need For Speed Underground 2 comes in at number two this week, ahead of Half-Life 2's number three debut, and racks up the eighth highest launch week for a PS2 title in the UK, improving significantly on the launch of the original last year.

Further down the chart, new releases thin out somewhat - EA's Medal of Honor: Pacific Assault on PC comes in at number 25, its sales no doubt affected badly by launching against Half-Life 2, while Midway's Mortal Kombat: Deception is at number 28 and Sony's karaoke game add-on, Singstar Party, slips in at number 40.

That leaves quite a number of titles on the missing in action list for the week - perhaps most notably, Namco's Nintendo-published RPG for the GameCube, Tales of Symphonia, which fails to make a dent on the Top 40 despite widespread critical acclaim.

Activision's PC title Vampire: The Masquerade - Bloodlines is also a no-show this week, despite being based on the Half-Life 2 engine technology and presumably hoping to do some business off the back of the hype for that game.

Among the other games which disappeared without trace this week are several GBA titles - including Nintendo's own Mario Vs. Donkey Kong - and the latest incarnation of Worms, Worms Forts Under Siege, on PS2, Xbox, and PC.