Stephen Sackur speaks to the renowned economist Ian Goldin, who wants to reframe the debate around migration. He’s been a senior official at the World Bank, an economic adviser to Nelson Mandela and he’s now professor of globalisation and development at Oxford University. His latest book, The Shortest History of Migration, illustrates the centrality of movement to the evolution of humanity – from the earliest human travellers leaving East Africa some 300,000 years ago to all of the people seeking sanctuary and prosperity across today's national borders. Migration is, right now, a hot and contentious topic. Powerful political voices across the world link migration with insecurity, crime and cultural breakdown. Others say migrants bring new ideas and energy and are vital to economic growth. It seems no amount of border security will stop people wanting to move; indeed, global heating and political instability are likely to see the numbers increase. Will migration, and how we deal with it, be the defining issue of this century?