Sony's PS Vita hasn't been out in Japan very long, launching in December 2011, however after a promising start its sales have plummeted, dropping to 18,361 in week five.

Although you'd expect a steady decline in sales after any big launch the week five figures constitute a 95 per cent drop on the very decent week one figures of 324,859. This is a serious bit of free fall for the console and sullies the PS Vita's 500,000 units-sold milestone.

To be fair all handheld consoles have taken a bit of a hit post-Christmas, namely the PSP and 3DS, however the Vita is lagging behind and when you consider its recent launch it doesn't make for good reading; the Nintendo 3DS coming in with 100,668 units sold and the PSP at 22,538, both ahead of the aforementioned Vita figure of 18,361.

Sony will certainly be hoping for better figures come the PS Vita's worldwide launch in February and with some top-game titles in the wings providing that all important sweetener for potential customers, it could be a very different story.

First Look: PlayStation Vita review