Welfare effects of liberalisation can vary according to the type and effectiveness of regulation. The British case-study that is object of this research report is a case of good, competent, and strong regulation. Other countries are exploring their way. I am convinced that in the British case liberalisation has benefited significantly from a good regulation, which has included provisions for the quality of service and has provided energy markets with analytically grounded and incentive-oriented tariffs, and with clear and stable rules, so that markets develop and tariffs can be gradually phased out in all but naturally monopolistic activities.