Abstract: The energy market liberalisation process in Europe is increasingly focused on electricity market integration and related cross border issues. This signals that the liberalisation of national electricity markets is now closer to the long-term objective of a single European energy market. The interface between the national electricity markets requires physical interconnections and technical arrangements. However, further progress towards this objective also raises important issues regarding the framework within which the integrated market is implemented. This paper reviews the progress towards a single European electricity market. We then discuss the emerging issues of market concentration, investments, and security of supply as well as some aspects of market design and regulation that are crucial for dynamic performance of a single European market.