Orange has launched the first credible Windows-powered smartphone and fired the first shot in what could become a bloody techno-tussle.

Although its SPV phone is only considered 2.5G technology, Orange believes it will pave the way to acceptance of true 3G capabilities.

UK buyers will be able to buy the handset within a couple of weeks. At the same time the SPV handset - developed for Orange by Taiwanese firm HTC - will have competition from models by Samsung and Sendo, also due for launch, which both support the Microsoft-based platform.

However, competitors will have to come up with aggressive pricing plans and applications packages if they are to beat Orange at its own game.

They could find this tough as both the Samsung and Sendo model are slightly more expensive than the SPV, which Orange will sell for £179 plus 12-month contract.

Orange will also be targeting the mainstream consumer and business markets in one shot, and has exclusive rights for 12 months to sell the HTC handset, which is bundled with an attachable camera, USB cradle and a Secure Digital/MultiMedia Card expansion slot, allowing for storage cards of up to 256MB to be added.

To tempt users to sign up for GPRS, Orange is offering to provide the service at a catch-all price of an extra £6 per month on top of its normal pricing plans.

Richard Brennan, executive vice president of OrangeWorld and Brands, called it "an all you can eat" service. But, admitted the company, customers can only download 10MB of data per month. Users will be fine if they just browse, but if they log on to graphics or data-heavy websites, or receive email or messages with large attachments, they could be in for a nasty shock. Once that initial monthly 10MB is used up, charges rocket to around £4 per 500KB.

The Microsoft software supports services such as photo messaging (MMS), email, calendar, contacts, instant messaging, text messaging, web browsing and audio and video playback. The phone will also act like a low-level Pocket PC personal digital assistant.