The OnLive gaming service went online in the UK yesterday. It's been running already for a few months in the USA and has been surprisingly low-key in its marketing, despite the fact that it is - potentially, at least - one of the most revolutionary steps forward in PC gaming history.

Up until now, the ability to run a game on your PC has been determined by the specifications of its components: how much memory it has, how much hard disk space and, most importantly, how powerful and capable your graphics card is. Playing games on PC has traditionally been an expensive proposition, requiring a reasonably heavy outlay to start with (usually around £500 at a minimum in the UK, more expensive than even the PS3 at launch) and then requiring upgrades every few years to stay current. An awful lot of traditional PC gamers got tired of this treadmill and with the arrival of the current consoles jumped ship a few years back.

OnLive essentially removes almost all of these barriers in playing a game on your PC. All you need is a keyboard, mouse and a reasonably good internet connection.

Basically, it's cloud gaming. The actual game is running on a super-PC somewhere else in the world. Your commands (mouse movements and keyboard processes) are transmitted to the remote PC and the graphics are updated and fired back at your PC, which displays the transmitted image. Achievements and saved games are stored on the cloud server. Nothing is stored on your PC (or Mac) at all, save only the OnLive app. OnLive's technology is based around reducing lag and latency as much as is technically possible, and the results so far are extremely impressive.

For the purposes of trying out the service, I chose to play SPACE MARINE, a virtually brand-new release. My PC is a five-year-old single-core machine that would barely be able to boot the game, and would not be able to play it at all even with all the details on minimum. On OnLive, the game runs at reasonably high spec. Image quality is not as 100% crisp and stunning as it would look running natively on a top-tier machine but compared to, for example, not being able to run the game at all, it is excellent. The speed of the game is stunning. There is no discernible lag or latency at all. I move the mouse and the character responds instantly. I have worse lag on playing some games off the hard disk. I played most of the game in a single 5-hour sitting and encountered no slowdown either (and SPACE MARINE can get pretty hectic at times, with huge outdoor areas and hundreds of Orks on-screen at once).

I haven't tested other games yet, so experiences may vary. In addition and probably crucially, I have an excellent broadband connection: a 10mb service from Virgin UK, plugged directly into the cable (no router) and my house is very close to the exchange. I suspect running the service on a shared router with a slower speed will be a dicier prospect.

Aside from the internet speed issue, there are a couple of other drawbacks. Obviously, nothing from the game is sitting on your hard disk, so creating and running fan mods or altering source files is of course impossible. The service also only works online, so in that respect is the ultimate form of DRM, but that is inherent to the service. Also, whilst the games look great, they definitely don't look as good as running a game natively on a top-tier system at high resolution. But then that sort of gamer is not whom the service is aimed at.

On top the obvious benefits of the service, there are quite a few others as well. Firstly, most of the games have trial periods attached to them, allowing you play the first 30-60 minutes of the game for free before you buy. This is obviously useful to everyone, even hardcore gamers, allowing you to try before you buy (a vital service in these days where demos either don't come out at all, or only months after the game is released). Secondly, the service can output to PC, Mac or even a tablet. The (somewhat under-sold) side-effect of this is that Mac users can now play every single PC game ever released (er, on the service) without having to faff around with a Windows installation or hoping that a Mac version of a game is released. Thirdly, the pricing model allows you to pay for 'access' to a game for a few days rather than buying the whole thing. For example, I knew from reviews that SPACE MARINE's single player campaign only lasts for 5 hours, so I paid £4 for a 5-day pass to ensure that I'd have enough time to complete it. Basically, it has a built-in, instant-access rental service.

The prospects for the service are amazing. Obviously there are the caveats that you need a good Internet service and that the service is in its infancy. How well it works at peak times with millions of people trying to log in at once is something that remains to be seen. But right now, it's a really impressive service. Plus when you sign up you get a full game for a quid, so for the outlay of £1 I can now play DEUS EX: HUMAN REVOLUTION, which would melt my PC if I tried to run it 'properly' :-)