Photos: Microsoft Windows Phone 7's UK launch in pictures

WP7 handsets galore and a surprise performance from Stephen Fry...

Microsoft yesterday presented to the world its latest assault on the smartphone software market.

Rather than announcing yet another iteration of Windows Mobile, Microsoft has built its newest mobile operating system - Windows Phone 7 - from scratch.

The London launch of the operating system took place at the ICA - a venue better known for its arts events.

Making a surprise appearance at the London launch of Windows Phone 7 was actor and tech celeb Stephen Fry.

While better known as an Apple user, Fry said he welcomed Microsoft's mobile efforts.

"I want biodiversity, the more players there are the more it drives creativity and innovation, the more thrilling the space becomes. Will I be using my Windows Phone 7? Yes," he said.

Andy Lees, president of Microsoft's mobile communications business, was also at the London launch. According to Lees, Windows Phone 7 has meant a whole new approach towards mobile for Microsoft. By focusing more on consumer applications and layouts, Microsoft is hoping to broaden its appeal while holding onto (and potentially attracting back) its traditional base of business users.

Microsoft CEO Steve Ballmer appeared via video link from New York to announce the debut of Windows Phone 7, which he claimed would sport an altogether more user-friendly OS.

The CEO of Microsoft proudly showed off nine handsets. Each will have a minimum spec set by Microsoft, including a four-inch touchscreen and three buttons across the bottom of the handset - back, home and Bing search.

With the device specifications set in stone, mobile operators will have to rely on apps and services to set themselves apart, such as Vodafone's planned 360 My Web offering.

The operator, however, has yet to reveal just which services will be available through 360 My Web.

HTC meanwhile hopes to mark itself through the HTC hub - a collection of apps and services including weather information and security features such as remote wipe.

The HTC hub is shown here running on a new HTC device, the HD7.

The HTC handset comes with a kick stand, allowing users to watch PowerPoint presentations and videos handsfree.

Samsung also debuted a Windows Phone 7 device - the Omnia 7, shown above.

Designed specifically with business users in mind, the Venue Pro by Dell is the only handset with a Qwerty keyboard. The keyboard slides out of the bottom of the handset and makes the Dell the largest of all the WP7 phones.

WP7 handsets come pre-loaded with Microsoft Office Mobile which allows users to view, edit and comment on Office documents directly from the handset via Microsoft's SharePoint service. There's also Microsoft's note-taking software OneNote on the platform which saves documents in the cloud via Redmond's SkyDrive cloud storage service.

It's also possible to follow PowerPoint presentations as they are delivered via the handset while continuing to contribute to a conference call.

Shown above is Excel running on a WP7 phone which comes with pinch and zoom function, giving users an easy way to navigate around data-rich spreadsheets.

WP7 offers calendar synchronisation with Outlook and Windows Live - allowing WP7 mobile users to sync both work and leisure appointments with the handset.

For consumers, there's also the Orange Wednesdays app - a Windows Phone 7 version of the operator's buy-one-get-one-free cinema ticket promotion.

For more on Windows Phone 7, see Photos: Windows Phone 7 devices - the launch line-up.