Nokia chief executive Stephen Elop announces the company's alliance with Microsoft
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Nokia's Stephen Elop on Microsoft deal to use Windows

Nokia and Microsoft have formed an alliance that will lead to the Windows phone operating system running on Nokia smartphones.

The deal means that Nokia's existing operating systems will be sidelined.

Speaking at the launch of the partnership, Nokia's chief executive Stephen Elop revealed that there would be "substantial" job losses as a result of the tie-up.

Earlier this week he sent a memo to staff warning that the company was in crisis.

Mr Elop said the game was changing when announcing the deal in central London.

Go to next video: Why Nokia and Microsoft joined up