"The partnership announced today provides incredible scale, vast expertise in hardware and software innovation and a proven ability to execute," said Microsoft CEO Steve Ballmer as Nokia and Microsoft today announced plans for a broad strategic partnership to build a new global mobile ecosystem.

“Ecosystems thrive when fueled by speed, innovation and scale," Ballmer said, adding: "I am excited about this partnership with Nokia."

"It’s now a three-horse race," said Nokia President and CEO, Stephen Elop (pictured)...a reference to iPhone/iPad giant Apple.

In a note to Nokia employees sent earlier in the week, Elop had characterized Nokia's reliance on the Symbian OS as follows:

"There is a pertinent story about a man who was working on an oil platform in the North Sea. He woke up one night from a loud explosion, which suddenly set his entire oil platform on fire. In mere moments, he was surrounded by flames. Through the smoke and heat, he barely made his way out of the chaos to the platform's edge. When he looked down over the edge, all he could see were the dark, cold, foreboding Atlantic waters.

As the fire approached him, the man had mere seconds to react. He could stand on the platform, and inevitably be consumed by the burning flames. Or, he could plunge 30 meters in to the freezing waters. The man was standing upon a "burning platform," and he needed to make a choice.

He decided to jump. It was unexpected. In ordinary circumstances, the man would never consider plunging into icy waters. But these were not ordinary times - his platform was on fire. The man survived the fall and the waters. After he was rescued, he noted that a "burning platform" caused a radical change in his behaviour.

We too, are standing on a "burning platform," and we must decide how we are going to change our behavior."

The alliance with Microsoft is certainly a change. Under the proposed partnership Nokia intends to adopt Windows Phone as its principal smartphone strategy, innovating on top of the platform in areas such as imaging, where Nokia is a market leader.

Nokia would help drive the future of Windows Phone and contribute its expertise on hardware design, language support. The company would help bring Windows Phone to a larger range of price points, market segments and geographies.

Nokia and Microsoft, the companies said, would closely collaborate on joint marketing initiatives and a shared development roadmap to align on the future evolution of mobile products.

Under the proposed partnership Bing would power Nokia’s search services across Nokia devices and services and Microsoft adCenter would provide search advertising services on Nokia’s line of devices and services. In return, Nokia Maps would be a core part of Microsoft’s mapping services.

Microsoft development tools would be used to create applications to run on Nokia Windows Phones, allowing developers to easily leverage the ecosystem’s global reach.

"Today, developers, operators and consumers want compelling mobile products, which include not only the device, but the software, services, applications and customer support that make a great experience," said Elop, adding:

"Nokia and Microsoft will combine our strengths to deliver an ecosystem with unrivalled global reach and scale."