Ban Ki-Moon, UN Secretary-General, says he will come to the London Summit to speak for more than 170 nations not represented among the G20 – especially the poorest countries.

He warns that the economic crisis could quickly evolve into a political crisis among the poorest nations. 'There is a thin line between failed banks and failed states,' he says. 'We face a genuine threat of social unrest, even conflict.'

The UN Secretary General outlines his four priorities:

1. We need a substantial and truly global stimulus package.
2. We must stand firm against protectionism.
3. We need sustainable growth that recognises the threat of climate change.
4. We must rethink the international financial institutions to reflect the changing economic and political landscape.