Sony has mistakenly unveiled the new edition of its handheld console, the PSP Go. The biggest change is that the UMD drive has gone, leaving a considerably smaller and lighter console.

The Go (pictured via Eurogamer.net) isn’t expected to get an official airing until tomorrow at the E3 video games conference. However, a video detailing the new console is part of the June edition of Qore, Sony’s online video magazine, which briefly became available ahead of schedule over the weekend. (Of course, it’s entirely possible the publishing ‘blunder’ was a way of sparking publicity.)

As part of the clip, Sony’s John Koller reveals that the device is 43 per cent lighter than the existing PSP-3000, largely because the UMD drive has been replaced with a Bluetooth/16 GB flash memory combination, with games downloaded directly to the memory rather than bought on physical media. The reduction in size hasn’t come at too much expense to the screen, which is 3.8” (compared with 4.3” on the PSP-3000).

The Universal Media Disc format had been designed as a way to get the storage advantages of a DVD on a portable console, plus makes it possible to sell legal movies for the PSP. In practice the format proved too easy to hack, while movie discs had the twin problems of the UMD format usually requiring DVD extras to be ditched to save space, and the reluctance of buyers to purchase a disc exclusively for the console, particularly if they already owned the title.

Though new incarnations of both Grand Turismo and Metal Gear Solid will appear on the Go, the clip gives the impression the device may be aimed at casual gamers with many titles being shorter games (presumably at a low price) designed to be downloaded and played on impulse.

It appears many of the other core features of the PSP, such as playback of various audio and video formats, and slick integration with the PS3, will be present on the new console. Pricing isn’t yet confirmed, while the release will be sometime this fall.