If you took all the sports cars out of Jay Kay's and David Beckham's respective garages, and got them to mate (assuming a universe where cars could indeed go forth and multiply), and then left them for many, many decades, the resulting automotive family would no doubt be massive, but still not as large as the huge array of driveable vehicles in Forza Motorsport. There are 230 cars to be precise, which is a figure more suited to a motor show than a game.

However, there's more to Forza than sheer weight of numbers. It's a driving simulation as opposed to the usual console arcade fare such as Project Gotham Racing. This means that there's an extensive range of car set-up options, so you can tune your gears, down-force, brake balance and so on, hopefully trimming seconds off your best lap times. There's a host of telemetry options which allow you to view graphs and charts of tyre wear, g-forces and all manner of technical info, so those who are serious about their racing can go into real depth on the tuning front.

That aside, the real meat of a simulation is in the driving model, and Forza's feels suitably challenging to drive without being over the top. There are help options for novices just in case you do find it too exacting, such as traction control and an ideal racing line which can be drawn over the track, but with all the help turned off it feels about right to us. You certainly can't take liberties with corners and must use proper race-line braking and turning, but it isn't so harsh that any slight mistake will spin and flip you off the track. The computer drivers are challenging too: they move to block you overtaking, for example, not merely driving the same lines robotically.

Forza isn't limited when it comes to play modes, either. There's an arcade race section for those who just want to dip into a competition, and a full on career mode, as well as time trial and practice lap facilities. The full career lets you choose a starting car and gives you a little money in the bank, the idea being to win races and accumulate more dosh. The more you earn, the more turbochargers and super slick tyres you can buy, plus further races are unlocked, boasting still bigger prize money. Cars can be won for coming first in a whole series of races, or you can buy your own, so eventually you'll be able to afford that top-line Ferrari or Porsche.

The races themselves are a mixture of circuit tracks, one-way street courses and more arcade style affairs (for example, zooming through a dockside complex, dodging between lorries and transport containers). There's a good variety here, in terms of both the format and the actual look of the tracks. Visually, the background graphics are very impressive and the cars look excellent, particularly considering that they're highly customisable. It's possible to purchase new alloys, change the spoilers, air dams and the like, select from a number of paint jobs and add a pretty much unlimited amount of stickers and decal designs.

While we're on the subject of customisation, it's good to see that Microsoft has allowed the option of custom soundtracks, so you can drive to your own Xbox tunes and not the usual 'tsh-tsh-tsh' in-game music drivel. The sound effects themselves are worthy of a mention on the basis of the cars, which all have realistically different engine tones. After a while, you can actually tell that it's an Impreza right on your tail, just from the hoarse and thrashy engine notes.

There's tons of longevity in the career mode, and the multiplayer mode is similarly well endowed, boasting a two-player split-screen option backed up by a pile of Xbox Live features. These include a full online ranking system, a quick match option, a detailed match search, plus an online career mode. The latter is particularly impressive, as it lets you progress in your career mode by racing human opponents, matching players to your skill level using the online rankings. The online experience is lag-free, too.

There's very little to fault with Forza. Our sole complaint is the in-game menus, which are pretty clunky all round, and particularly confusing on a couple of screens (such as the decal customisation, to give an example).

If we wanted to be picky we could moan about the game menus, but that minor bugbear is completely cast into the shadows by the overall excellence of this racing game. It's the Xbox's answer to Sony's Gran Turismo titles. It's a blast both offline and on Xbox live, and a must-play driving simulation, simple as that.