Energy markets in many countries have been extensively liberalised in recent years as part of the revival of market economics. However, though 'everyone may believe in markets now', there are differences of opinion about what constitutes a competitive market. The perfect competition paradigm persists and leads to demands for state regulation to counteract 'imperfections' and failures'. Energy economists should look more sceptically than they generally do at these calls for regulation, most of which have little to do with the Public interest ': in the long run the accretion of regulation may, lead back to extensive state control.