When you've been number one for so long, everyone will try to bring you down. Companies in the Far East are now cleaning up by selling cheap handsets in emerging markets, while Android and iOS have destroyed the huge lead Symbian once enjoyed.

A lot of this can be attributed to bad management and planning within Nokia, but the company is now hitting back with what it hopes will reverse the downward trend.

Firstly, it created a new range of phones under the 'Asha' brand for emerging markets. Secondly, it launched the 'Lumia' brand for its high-end smartphone line, introducing Windows Phone as its new chosen operating system.

The Lumia 800 is the flagship handset, and the release is significant. It's make-or-break for Nokia, and Microsoft is also desperate for a device to sell its operating system to the masses and gain some market share. In just over a year, Windows Phone has failed to establish itself as a serious competitor to Android and iOS.

Windows Phone is an excellent operating system, but Microsoft still has to accept that many people will think of it in the same way as Windows Mobile, which was awful. Microsoft started from scratch with Windows Phone, but many people will never appreciate that fact, or care.

With a huge advertising campaign, along with support from all of the major retailers and networks bar O2, everyone will know about the Lumia 800 in the coming months.

It's arguably the nicest looking Windows Phone device to date, as Nokia has approached it from a consumer perspective - so far, other Windows Phone devices have been rather dull and business-like.

Any colour, including black

The Nokia 800 also comes in black (the colour of the review model) but the two colours that will generate the real excitement are the bright magenta and cyan models. The cheaper phone, the Lumia 710 (which may not be released in the UK) even comes with changeable covers.

In the box, you also get a free protective case, some rather cheap headphones, a USB cable, and a charger. The box itself is a potential collectors piece, as Nokia follows the likes of Apple in making the unboxing an experience in itself.

Personally, I'm more interested in the phone than in a box that gets chucked in a cupboard.

The first thing I needed to do was get a micro-SIM. Obviously, anyone buying the phone on contract or as an upgrade will get one of these included, but when it goes on sale SIM-free in early 2012 be aware that you'll need a new SIM or to take to your existing one with a pair of scissors and some steady hands.

Tough choice

The casing of the phone is almost identical to the MeeGo-powered N9, which only got a limited release in some rather random countries around the world.

The polycarbonate plastic shell is incredibly tough and warm to the touch, as well as coping with bumps and scrapes well. The plastic is the same colour all the way through, so if you chip the casing you won't suddenly find white specks. Not that there's much chance of you denting it in the first place.

The front screen, housing a 3.7-inch AMOLED display (480x800 pixels), is made from tough Corning Gorilla Glass and has Nokia's ClearBlack technology, which minimises glare.

Below the screen sit the three Windows keys: 'back', 'home', and 'search'. On the side you'll find the volume keys, a 'power/lock' button, and another for the camera, while the top has the 3.5mm headphone jack (which is exposed to the elements) and a pop-open cover to hide the micro-USB port.

Flip the phone over and there's an 8-megapixel camera with Carl Zeiss optics and a twin-LED flash, sitting alongside the Nokia logo on a mirrored panel.

Inside the phone is a sealed 1,450mAh battery, and the phone is powered by a 1.4GHz Qualcomm Snapdragon processor with Adreno 205 graphics co-processor. Until Microsoft upgrades the operating system to support dual-core processors, this is the fastest you're going to get.

Powerful engine, heavy on fuel

The good news is that it's very quick, but then Windows Phone has always been quick. All the animated transitions and user interface effects are hardware-accelerated. It seems crazy to think that the GPU wouldn't be used for such things, but that's exactly the case on Android devices, until the release of Android 4 (Ice Cream Sandwich).

The bad news – for Nokia at least – is that anyone looking for the fastest smartphone may be turned off by Windows Phone, but you really don't need any more power than is on offer here for the vast majority of tasks.

The simplicity of the user interface is what makes things so quick, and the animated transitions sneakily buy the processor some time to do things in the background, so apps appear to load almost instantly.

Microsoft has also been strict with developers when it comes to allowing apps to run in the background since the release of Windows Phone 7.5 (Mango), which ships on the Nokia 800.

This keeps the power consumption down when applications are sent into the background. As an optional power saving measure, when your battery begins to get critically low you can turn off multi-tasking altogether. It's easy to swap apps by holding the 'back' key for a second or two and selecting the app from its visual thumbnail.

The problem is, no matter how good the operating system is at managing things, once you've set it up to work with all of your various email and social networking services it'll start sucking power. I failed to keep the phone going for longer than 12 hours between charges, although Nokia has already told me that it will release an update soon to address some issues it has discovered.

12 hours will cope with a normal working day. It's just the going out after work bit that you'll struggle on. Giving it a midday top-up is highly advisable here, but that's the same advice I'd give for any smartphone.

Stark contrast

If you're coming from another Nokia, don't expect many similarities – besides being able to make calls, send texts, and read email. Oh, and a Nokia logo above the screen.

There's Nokia Maps (in beta), Nokia Drive (a turn-by-turn navigation system), a new app called Nokia Music, and an app that highlights new and exciting apps chosen by Nokia, but everything else is pure Windows Phone.

This review isn't the place to go into too much detail about Windows Phone, but here are the basics in case you're a new user.

Microsoft is pitching Windows Phone as an operating system that 'puts people first'. What this means, when you take away all the marketing speak, is that you are initially presented with a Start screen that, rather than static app icons or widgets, uses Tiles that you can customise and place in order of importance.

A swipe to the left reveals your list of installed apps for people who are used to the iPhone/Android way of doing things.

Tiles serve as links to applications, or Hubs (there are individual hubs for things like photos, video, music, and games), while you can also add 'Live Tiles' that convey key information without ever needing to open the application, rather like a widget.

Windows Phone now makes it possible to add multiple tiles for a single app, so you can select different categories or topics, like sport results, news headlines, or weather forecasts.

The OS also contains support for a multitude of email and social networking services, like Facebook, Twitter, LinkedIn, Hotmail, Google, Outlook, and Windows Live. A 'Me' tile shows everything you've recently posted, as well as people who have mentioned you somewhere. You can also use this as a single location to check-in to a place, or make yourself available for one of the various chat services.

By combining contacts into groups you can communicate with loads of people at once and the phone is clever enough to detect the various services a friend uses and combine them all into one account (if it can't, for any reason, you can do so manually). What might start as a chat on Facebook could later switch to text messaging, while remaining within a single thread.

There are other cool touches, like grouping together conversations within emails and the on-screen keyboard detecting when you've pressed between two keys and working out the one you meant to touch.

Searching is with Bing, as you might expect from a Microsoft operating system. Windows Phone 7.5 now includes a new service called 'Local Scout' that finds things in your locality, like restaurants and shops, and there's Bing Music that identifies music by holding the microphone up to the speaker (Shazam also has its own app on Marketplace, too). Bing Vision lets you scan text and barcodes.

Camera

Here ends the Windows Phone lesson for the day, so back to the phone and the camera, which Nokia made a big deal of at the launch.

There's not much to look at, but with the combination of a Carl Zeiss lens and a sensor that works in low-light conditions, the camera is actually very good. Not as good as the N8, but certainly up there with the likes of the iPhone 4S and Sony Ericsson's Xperia arc and ray.

One of the best features of Windows Phone is the ability to launch the camera instantly by holding the 'camera' key for a few seconds. It means you'll always be able to take a photo quickly and not get bogged down with swiping to unlock, entering PIN codes, drawing patterns, or even waiting for your face to be photographed. Just hold and you're ready to go.

In video mode, the camera also has a tendency to hunt around for focus, which can spoil the results. Video is restricted to 720p, too, so there's still a bit of work to do there.

There's no front-facing camera on the Nokia 800, although that's only an issue for people who actively make video calls or use video conferencing. I'm fairly confident that that's a small number of people, so I won't consider the omission a deal-breaker.

You can elect to have pictures automatically uploaded to your free online SkyDrive account (you get 25GB free with your Windows Live account that you'll create when you get set up).

When you're uploading a photo to other services, like Facebook, the phone detects faces and invites you to add names. It can't do this automatically, but given the hit-and-miss nature of automatic tagging this is probably no bad thing.

Xbox inside

Microsoft wasn't stupid when it came to adding games to Windows Phone using the Xbox Live brand. It lets you share achievements with other Xbox gamers, play around with your avatar, and also play multi-player games – although there aren't many to choose from yet.

With the minimum hardware requirements being pretty high, developers have a level playing field for creating games, and it shows. There may be fewer games than on other platforms, but the ones that are there tend to be better than the tinpot freebies you find on the Android Market.

Games on the Marketplace can be quite expensive. For instance, Angry Birds costs 69p on iPhone and £2.29 on Microsoft's platform. The range of titles is good, with several high profile franchises represented, but you'll have to get used to the fact that gaming on a Windows Phone will cost you more than gaming on iOS or Android.

Microsoft boasts over 35,000 apps and growing, with a decent number of official apps for services like Facebook, Twitter, Evernote, and Spotify. Spotify for Windows Phone is probably the nicest mobile version, while Skype – a company now owned by Microsoft – can't be far away.

Installing apps is easy, and Marketplace keeps you informed of updates in its very own tile. New apps and games are also highlighted, along with music and video that you can purchase or rent.

A Zune pass is available for £10 a month to give free music access, although I'd recommend spending that money on a Spotify account instead.

Nokia Music is another way to get free music, with a series of mixes that you can stream to your phone. You can also download up to four mixes for offline listening, but the choice is fairly limited to begin with.

You can also copy music from your PC and Mac, with software available for both that syncs music, photos, and video, along with playlists, and makes a back-up of the phone. As with some other smartphones, you can also track the handset location via the web and remotely wipe the device if it's lost or stolen.

The Nokia 800 has 16GB of onboard memory and no card slot. Motorola recently revealed that it dropped card slots from its new Xoom 2 tablets because content is now more likely to be streamed from the cloud, and Microsoft has a similar vision.

If you want to fill the phone with HD videos to watch on a plane, you may find 16GB too restrictive, but if you're viewing online photo galleries or using Nokia Music or Spotify, you'll pretty much have that storage clear for an incredible number of apps and games.

Driving beyond the competition

Nokia Drive is a fairly basic navigation app, but Nokia is hoping that it'll set the Nokia 800 apart from other Windows Phone devices because it's only available on this handset.

In its initial release version, it works for getting you from A to B but little more. There's a lot of work to do before it can compete with rival services, although it's free and has downloadable maps for offline access (and saving money when roaming).

The problem for Nokia is that, besides Nokia Drive and Nokia Music, you could pick up an HTC, Samsung, or LG and it will work the same.

So what makes the Nokia more enticing than the rest? There's a unique design and build that makes it feel like you've actually got something new and not just another update of what you had before. Then there's the camera, which is excellent for all but video recording, and an excellent screen. It all combines to make the Nokia 800 feel special.

Nokia also has a strong reputation that hopefully hasn't been too badly tarnished in the last couple of years. Take away all the disappointed Symbian fanboys and there are plenty of people who still hold Nokia in high regard. And, deep down, even those Symbian fans are probably secretly hoping to be able to own another Nokia again one day.