This is our preview based on very limited time with the new OS, which mostly looks at the new Start Screen and takes you through the features Microsoft is promising for Windows Phone 8.

We're hoping to score some more detailed time to properly look through and snap all the new functionality the Redmond group is hoping to bring, so stick around if you're itching to know more.

Start Screen

There are going to be a lot more features in Windows Phone 8 (some of which might well come to Windows Phone 7.8 as well – there's no way of knowing until we find out what they actually are).

The only one Microsoft has shown in any detail is the new Start screen, which keeps the idea of live tiles that show you lots of information at a glance but gives you more options for the size of tiles and how you arrange them.

There's a new small tile size; you can fit four of those in the old Windows Phone 7 tile size.

The layout is completely flexible; press and hold the way you do on Windows Phone today and you can unpin a tile, drag it to a new position – or press the arrow that appears on the bottom of the tile to cycle through the small, large and medium sizes.

Even without the Zune-style 'trough' to remind you your other apps are on the right hand side, you only get two of what's now the medium tiles side by side, but there seven rows of small size tiles (or three and a half medium tiles) so you could cram in 28 small tiles if you wanted to.

More likely, you'll want a mix of small and medium tiles, with a couple of the 'double-wide' large tiles for apps that show a lot of information on a live tile.

That's no longer restricted to Microsoft apps, phone makers and mobile networks; any app can have a double-side tile now, and it can be a live tile that updates.

If you make a tile smaller, the tiles next to it don't move over automatically; if you make it larger, it does push the other tiles out of the way, so you may have to move tiles a couple of tiles to get the layout you want.

You can use small tiles to offset medium tiles (at the side or above) so you get a staggered arrangement instead of just grouping them in the space of one medium tile.

The new Start screen gives you even more live information because you can fit so many more live tiles on. You get more control than ever over which tiles get more space and which have just enough room to show their icon or the number of text messages or missed calls.

You can still have the Windows Phone 7-size tiles in two rows if you want, but if you think using a whole tile for Settings or your Me tile when you already know what your profile picture looks like is pointless, the three new sizes and the underlying seven by eight layout give you much more flexibility.