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. Regulatory Reform: Economic Analysis and British Experience (MIT Press), written with co-authors Mark Armstrong and John Vickers, was published in 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. For undergraduates I have taught Introductory Economics, Microeconomics, Macroeconomics, the Economics of Industry and International Economics. I have also taught environmental economics, and have taught Industrial Organization to graduate students. I was Head of Department between October 2019 and September 2020.