Today’s news that Nokia is buying out the mobile handset OS company Symbian must surely rank as one of this year’s most significant events in the telco space.

In the same release several of the mobile industry’s biggest players announced their intention to form the ‘Symbian Foundation’ to collectively develop a unified open-source operating system.

Having spent years competing in the Mobile OS space, Nokia, Sony Ericsson, DOCOMO and Motorola have all announced that they will donate their software (Symbian, S60, UIQ, MOAP) to the cause. Let’s just repeat that; four of the biggest companies in the mobile space, who invested years and millions of dollars into their software, are now ostensibly giving away their intellectual property to all-and-sundry.

So what motive is driving this unprecedented level of co-operation between the mobile giants? No-one’s going to sacrifice that much intellectual capital unless they stand to lose even more actual capital somewhere else. Something’s got their goose.

The big-players are surely trying to head-off some common threat. I think the BBC is incorrect to assume that this threat would be Android’s open-source Mobile OS ‘Android’ I think it’s more likely to be Apple.

Though the Symbian foundation is open to all, it seems unlikely Apple would join. Apple has always differentiated itself by providing in-house, innovative and fiercely-guarded software. Moreover, Apple is rapidly stealing the wind from the big player’s sails with the iPhone’s funky, sexy interface.

This should be an interesting fight.