Sales of Xbox 360 consoles are 18 per cent ahead of the PlayStation 3 in the UK since the launch of Grand Theft Auto IV, Chart-Track told Eurogamer today.

In even better news for Microsoft, official GTA IV sales figures for the first four weeks also reveal that the Xbox 360 is the format of choice for UK gamers, with 57 per cent of the total sales of the game on 360, compared to 43 per cent on PS3.

Current Chart-Track panel figures place sales of the game in the UK at over 1.3 million, meaning around 750,000 copies have shifted on Xbox 360, and around 570,000 on PS3. To put that into context, in under four weeks Rockstar’s opus has shifted almost as many copies as last year’s best-seller, FIFA 08 - a game which launched on every format under the sun.

The effect on driving hardware sales has also been more dramatic on 360 than PS3, according to Chart-Track’s figures. Comparing sales of both consoles for the four weeks prior to GTA IV’s launch to the four weeks since its launch, hardware units have risen on 360 by 47 per cent, compared to just eight per cent on PS3 - though it’s fair to point out that the release of GT 5 Prologue had already given PS3 a significant boost in the weeks leading up to GTA IV’s debut.

Looking at the year to date, the picture looks much rosier for Sony. Taking all 21 weeks of 2008 into account, sales of PlayStation 3 in the UK are 10 per cent ahead of Xbox 360. Prior to the launch of GTA IV, the PS3 boasted a 20 per cent lead on 360, so the gap is narrowing.

With exclusive downloadable content due on Xbox 360 later this year, it looks like this might be the deciding factor for many. But will it be worth the huge sums Microsoft paid Take 2? Let us know what you think.