Nokia has at last taken the wraps off its Lumia 1520 smartphone, previously known as the Bandit. It's the biggest handset Nokia has ever made, with the highest-resolution screen, the first quad-core processor, and the new Windows Phone operating system. We get our mitts on the handset to see if Nokia's latest creation is one of it's greatest ever.DesignAt 6 inches this certainly falls under the hideous name of phablet, or at least makes it the giant of the Nokia Lumia smartphone family. Despite the size it feels good in the hand, as all those curved edges on Lumias generally do. But it also makes you realise just how good the Lumia screens are and how you've always been longing for more screen real estate, even if you didn't realise it when\u00a0using the Lumia 1020, for example.That solid Lumia build quality is present in the 1520, but because of its large size and that 20MP PureView camera some might find it tipping the scales a bit into the heavy region. Though thanks to the slim form it will fit nicely into your pocket - well, it fit into ours, but any skinny jeans wearing folk best start accessorising with a man bag.ScreenThis is the best Lumia screen we've seen. It's not just the 6-inch size, or those absolute blacks we've come to expect from the range, but also that resolution jump to 1920 x 1080. Text feels sharper and that dark OS suddenly feels more alive with the clarity of white on black writing really coming into its own here.The extra tiles on the homescreen really work, thanks to the resolution and screen size jump. It feels totally natural as if the Start screen itself had been physically extended along with the phone. Colours are crisp and pictures appear bright and vibrant - we have to wonder what this will do to Nokia's otherwise good battery life when it comes to Lumias.PowerAt last Windows Phone is capable of supporting quad cores, and just at the right time. The Qualcomm Snapdragon 800 processor is so good that nearly every new device is arriving with it baked in. Now the Lumia range gets to enjoy the power too. Web pages, which we thought never ran fast enough on the Lumia 1020, now run as fast as you can. Everything just keeps up at a rate that leaves you enjoying the speedy transition graphics, as you know it's just for flair rather than an excuse for load times.We didn't have a chance to test the Snapdragon 800's capacity for outputting 4K video but did notice that this combined with the 2GB RAM meant opening the camera, snapping pics, and viewing the gallery is a much more fluid, high-paced experience than it's been on Windows Phone before.CameraThe 20-megapixel PureView camera takes all the smarts from its bigger 41-megapixel brother found in the Lumia 1020 and streamlines it. You might not get as much after-effect zoom, but instead you get a physically smaller form factor, more intelligent lenses and faster operation.From hitting the dedicated shutter button to taking a pic is fast enough for capturing a moment and the camera itself is smart enough to work out and shoot the situation near instantly.Nokia Camera app combines Smart, Pro and Video modes which are all easily accessible at a tap from the main camera screen. Sports mode and night mode are also available at a touch now. The Pro camera UI from the Lumia 1020 is included so you can adjust all the settings directly using the slider controls. It's brilliantly easy to use and shows newbs how changing settings affects the shot live. Like the Pro camera you can zoom in while shooting and then chose to zoom out after you've taken the photo.The HERE Maps team and PureView team have joined up to create Nokia Storyteller so you can search a map to find your pictures and videos. The ability to tap into folders that offer location-based sorting is also useful. From pictures you can pinch zoom out to the HERE map to search elsewhere for more snaps - could be useful while on holiday or shooting pics on a run. And you can now share it to Vine and Instagram, at last.OSThe new Windows Phone OS is all about helping Lumia catch up with the rest of the mobile market, by supporting quad-core processors. But the latest update also looks better in a functional way. The six tiles across the Start screen make it possible to have every app you could want easily accessible at a glance. The improved Hub options also mean that\u00a0more live tile options like Friends and Photos are updated automatically in nice large sizes.The new Driving mode is useful for safety on the road as it stops any incoming messages or calls from distracting you while you're behind the wheel.Multi-tasking is better than ever. We love the way you're now able to close individual apps, or the lot at once if the urge takes you. This is great for extending battery life where previously you were limited to hitting the back button to close everything one item at a time. We can see this being useful for shutting search windows while leaving open the resulting app - like a map you're now using after searching for a spot in Internet Explorer before.Smarter internet sharing lets you use the 1520 as a Wi-Fi hotspot without having to turn it on and off each time you use it. Pair a Windows 8.1 device with it once and every time you want to use it in future it will automatically turn on for you ready to use.VerdictThis is certainly the biggest Lumia phone Nokia has ever made, but is it the best? With the latest Windows Phone OS and more power than ever before it's the best on paper. In the hand it's an impressive device too which, to us right now, appears to be the best you can get with Microsoft's OS. But using a phone of this size day to day is another matter - one of preference. If your pockets can handle a handset of this size then this is for you, but if a smaller device is needed you may want to look elsewhere. If you're only priority is getting the fastest, most visually stunning Windows Phone handset in the world, then you need look no further.