Creating a tablet that doubles up as a laptop has proved a challenge - with this first hands-on, David Phelan finds out if Nokia have cracked it...

The Power Keyboard is the gadget you need if you want to use the Lumia 2520 as a real laptop substitute. Nobody likes typing on unyielding glass – just about the very first accessory Steve Jobs announced for the first iPad was a keyboard in case you were typing War and Peace. Though actually, why would you do that? It’s been, you know, written already.

Anyway, the Power Keyboard does what the title suggests, it brings proper keys and a battery to add to the Lumia 2520 tablet. The tablet, is considerably lighter than the fourth generation iPad, though no match in weight terms for its replacement, the iPad Air.

Of course, the keyboard adds extra weight, but it’s worth it. First of all, it shelters the beautiful tablet in a soft-touch matte-finish wrap, held in place by magnets. The tablet feels reassuringly well-protected. The case matches the curved edges of the 2520, making it equally comfortable to hold.

Then there’s the battery which considerably increases the battery life compared to the tablet alone, so you won’t worry about running out of juice even if you’re really putting it through a lot. The two together offer around 15 hours of usefulness.

The outside of the case also features two USB sockets, which is the kind of handy connectivity the iPad lacks. With the keyboard unfurled you access these slots from behind. They’re USB 2.0, not 3.0 which is a shame but they’re still useful.

Nokia CEO Stephen Elop holds the £399 Lumia 2520 at Nokia World.

Open it up and the laptop effect is persuasive: the tablet, held tightly at top and bottom in solid-feeling plastic clips, plonks magnetically into place next to the keys. The keys themselves are small but well-spaced and have enough bounce to make them a pleasure to use. They’re fast and responsive and you quickly feel you’re using a regular, if cosily small, keyboard. The keys include a dedicated Windows key to flip back to the Start screen. And there are direction keys to navigate a document or highlight text, say.

There’s also a trackpad which works splendidly, including recognising multi-touch so you can scroll up and down a document with two fingers, for instance. If the keyboard is resting on your knees, there’s a certain flimsiness to the trackpad but on solid surfaces there’s no problem.

Because the 2520 has a solid, physical connection to the keyboard there’s no waiting for Bluetooth to connect, either.

I used this set-up in Las Vegas at the Consumer Electronics Show and it felt every bit as useful as a regular laptop, but for the fact that Windows RT is fussy about what programs you can use, limiting your choice to the apps in the Windows Store.

The Nokia Lumia 2520 is a highly useful and enjoyable tablet. The keyboard adds an extra layer of usefulness. And since the tablet includes a sim card slot, you can use it and be connected wherever there’s a 3G or 4G signal.

The keyboard isn’t cheap – it goes on sale any day now for £150 – but it takes an already impressive tablet to the next level.