I am an Associate Professor in Economics and Wigmore Clarendon Fellow in Economics at Worcester College. My research is on theoretical models of pricing in imperfect competition, with a recent focus on price discrimination and its welfare effects. I have also worked on the regulation of privately-owned utilities. I am the author, with Mark Armstrong and John Vickers, of Regulatory Reform: Economic Analysis and British Experience (MIT Press, 1994). I have papers in the American Economic Review, The Economic Journal and the Rand Journal of Economics, and am a former editor of Oxford Economic Papers, whose board I now chair. For undergraduates I teach Microeconomics, Macroeconomics, the Economics of Industry and International Economics. I have also taught environmental economics, and have taught Industrial Organization to graduate students.