Ballmer says Nokia's Windows Phone will debut next week

Microsoft chief says handset will arrive at Nokia World in London

Nokia plans to unveil a Windows Phone handset next week in London, according to Microsoft chief Steve Ballmer.

Speaking at the Web 2.0 summit, the Microsoft CEO said that Nokia would be unveiling its first devices for the Microsoft platform at the Nokia World conference, which takes place at the Excel Exhibition Centre between the 26 and 27 October.

The two companies announced a strategic partnership in February, in a the deal that reportedly cost Microsoft as much as $1bn and will see Nokia adopt Windows Phone as the primary OS for most of its smartphone models.

Both companies have seen their smartphone operations sputter in recent years. Nokia's market share has shrunk in the face of fierce competition from rivals, while poor Windows Phone 7 sales led to Ballmer missing out on his annual salary bonus.

Ballmer's revelation comes as the smartphone market once again finds itself in flux. Former powerhouse Research In Motion (RIM) has suffered falling sales for its BlackBerry platform while Apple, which recently debuted its iPhone 4S, reported lower-than-expected sales for its handsets last quarter.

Meanwhile, Google acquired Motorola's handset operations in the summer, in a move that some analysts have suggested could drive rival hardware vendors from Android and to the Windows Phone platform.