The Nokia Lumia 1520 is a trailblazing 6-inch smartphone that forges a path for Windows Phone 8 into true high-end territory. And what a swathe this oversized phablet cuts - it's huge.

However, Windows Phone 8 itself seems reluctant to follow. While still an attractive OS, it needs optimising for the Lumia 1520's large Full HD display. So too does its app ecosystem, which remains well below par.

Still, there's no denying that this is the most capable Windows Phone device yet, with a fine camera and tip top performance.

We liked

The Nokia Lumia 1520 is a well put together smartphone with Nokia's typical build quality.

Its 6-inch 1080p display is a thing of beauty, and is a great way to watch videos and view photos on the go.

Nokia has produced another excellent camera phone here, learning lessons from the Nokia Lumia 1020 and the Nokia Lumia 925 to produce a very well balanced snapper.

We disliked

Windows Phone 8's lack of flexibility really holds the Lumia 1520 back from being the phone it could be. Too many elements fail to capitalise on the large, sharp display.

There's also no denying that this is a ridiculously large phone, and whipping one out in public will be as embarrassing as it is tricky to wield for those who appreciate a little subtly and mobility from their phones.

Then there's that age old problem of the Windows Phone 8 ecosystem, which still lacks apps, not to mention a video store to fully capitalise on that cinematic screen.

Verdict

The Nokia Lumia 1520 is an absolute beast of a phone that we suspect only the large-handed and generous pocketed will be able to live with day to day.

Those who accept the challenge will find the most capable Windows Phone 8 device yet, with top-of-the-range specs that include a stunning 1080p display and a superb 20-megapixel camera.

Despite its size, however, the Lumia 1520 feels like it's missing something. Only when the Windows Phone OS allows itself to be moulded and expanded into this new super-sized form factor will it feel complete.