He is also the United Nations Special Rapporteur on the Human Rights of Internally Displaced Persons. He joined the Department of Law at LSE in 1996 and lectures in international law and human rights. He was formerly a Research Fellow at Wolfson college, Oxford, with Lectureships in Law at Exeter and St. Catherine's colleges, Oxford, and a Crown Prince of Jordan Fellow, Queen Elizabeth House, as part of the Refugee Studies Centre, Oxford.