Nearly thirty years after the Single European Act of 1987 the EU energy market remains characterised by national silos and limited interconnectivity. However, the Ukraine crisis is a shock event. It has brought home to all member states the general need for a more coordinated energy policy. The single energy market forms a key pillar of the energy union package launched by the European Commission in February 2015. Energy union is now a shared priority of the Presidents of both the Commission and the Council. Therefore, President Putin’s decision to cancel the South Stream pipeline may also have far-reaching impacts on the further development of EU energy policy. To coincide with the launch of our latest research on this topic, Refuelling Europe: A Roadmap for Completing the Single Energy Market, the Martens Centre is pleased to host an international panel of experts to discuss the new realities facing EU energy policy. Is the further development of the single energy market still the best mechanism to reach the EU’s three goals of an energy supply that is cost competitive, secure and environmentally sustainable? How will the cancelling of South Stream impact upon member states in south east Europe? Does the ‘southern gas corridor’ represent a viable opportunity for the EU to diversify its energy supply?