Relations between Khartoum and Juba have been tense since the independence of South Sudan two years ago. And no issue is more prickly that the status of Abyei, a region that sits on their common border. A proposal to hold a referendum to decide if the oil-rich region should remain in Sudan or breakaway to join South Sudan have run into difficulties. John Young, the author of The Fate of Sudan, who says the issue of Abyei could turn ugly.
