Timothy Garton Ash, Professor of European Studies, Oxford; Columnist, The Guardian; Twitter @fromTGA

Bill Clinton said that China trying to control the internet was like trying to nail jello to the wall. But the Chinese Communist Party has been trying to prove him wrong; all over the world sovereign states are attempting to reassert their control over the internet. American private powers such as Google and Facebook are coming under sustained criticism, not least in Europe. Is the internet losing its original libertarian promise? Has the United States — and Silicon Valley — mishandled this over the last 20 years? What can still be done about it? Timothy Garton Ash is leading a major, 13-language research project in free speech at Oxford University, (which can be viewed at http://wwwfreespeechdebate.com/en). He is also writing a major book on global free speech in the age of mass migration and the internet. He will discuss one of the major challenges of our time.

Timothy Garton Ash is professor of European studies in the University of Oxford, Isaiah Berlin Professorial Fellow at St. Anthony's College, Oxford, and a senior fellow at Stanford's Hoover Institution. He is the author of nine books of political writings or "history of the present," including The Magic Lantern: The Revolution of '89 Witnessed in Warsaw, Budapest, Berlin & Prague, The File: A Personal History, In Europe's Name and, most recently, Facts are Subversive. He writes a widely syndicated column on international affairs in The Guardian and is a regular contributor to the New York Review of Books, among other journals. Awards he has received for his writing include the George Orwell Prize.

Here's a chance to hear him identify the current threats to free speech.