Nokia has long been rumoured to be launching the Nokia Lumia 900, a bigger version of its current Windows Phone 7 flagship, the Nokia Lumia 800, with a 4.3-inch screen for the US in 2012.

However with nothing official announced we have to turn to rumours, speculation, and the odd bit of guesswork for the time being.

Two new clues have appeared over the last couple of days including some official looking marketing material and an official video by Microsoft showing users how to use Hotmail on their Windows Phone 7 smartphone.

The leaked images, discovered just before Christmas, were billed as the Nokia Lumia 800 coming in an array of new colours - yellow and white if you are interested.

However Pocket-lint believes, on closer inspection, that the marketing images found by French site MonWindowsPhone are in fact of the Nokia Lumia 900, not the Lumia 800.

Two reasons, we believe, give the game away. Firstly the screen dimensions look bigger than the Lumia 800's 3.7-inch screen, and secondly the images also reveal what appears to be a front facing camera in the top right corner of the phone - something that isn't present on the Lumia 800.

Adding fuel to the Lumia 900 fire is an video by the UKWindowsLive team on YouTube. In it a girl shows just how easy it is to sync with her Hotmail account to get emails on the go.

The phone is only shown briefly however again appears to be a lot wider and bigger than the Nokia Lumia 800 we've got sitting here in the Pocket-lint office.

Of course it could be that the woman has incredibly small hands, but we very much doubt it.

The plot thickens as they say.

What do you think? Is it the Nokia Lumia 900? Let us know in the comments below.