An overview of the transition to smart energy systems in Great Britain, covering the concepts of smart grids (networks) and smart metering. It describes the policy and regulatory framework at a domestic level, within the government's broad Smart Systems and Flexibility Plan and smart meter rollout programme. It outlines funding for smart grid innovation and explains the difference between different intelligent meter standards (advanced, SMETS 1 and SMETS 2 meters). The note discusses EU initiatives on smart metering.