Inequality - the world's greatest threat?

I've just been reading Stephen Hawking... not the 'Brief History of Time' but a piece in The Guardian on the 2nd of December.
He talks about how he lives in a privileged 'bubble' in Cambridge, and how this connects with ideas of inequality, which he sees as being the world's major threat.

"We need to break down, not build up, barriers within and between nations. If we are to stand a chance of doing that, the world’s leaders need to acknowledge that they have failed and are failing the many. With resources increasingly concentrated in the hands of a few, we are going to have to learn to share far more than at present".

Check out Unlimited World

This has been launched with some new content, including a good article by Ben Saunders.