The poor of the developing world and the middle classes of the developed world seem unlikely allies. But, according to economist Branko Milanovic - whose main field of interest is the relationship between globalisation and inequality - the two groups are the biggest losers as a result of globalisation. Milanovic is a lead economist at the World Bank research department and a senior associate at the Carnegie Endowment for International Peace.

The disparity between rich and poor is greater now, Milanovic says, than at any time in recent history. In fostering dissatisfaction and migration, this inequality can have a critical impact on global stability. Everywhere, a wealthy elite thrive, while the poor and middle classes lose out on globalisation's potential benefits. As people within societies become more dissimilar, says Milanovic, social problems increase until a backlash occurs. Milanovic doesn't necessarily see an apocalyptic vision ahead. But, as he tells Rachel Rawlins, political decisions are being made in increasingly dissimilar nation-states. What's needed, he argues, is more of a polity at the global level - to address truly global issues such as poverty, inequality and climate change.

Rachel Rawlins talks to Branko Milanovic Listen on your computer / Download to your computer (9.47mins)