The European Union’s latest effort to get to grips with its eastern frontier comes days after it celebrated the fifth anniversary of its historic enlargement into the former communist bloc.

The eastward expansion healed cold war divisions and helped the ex-communist states to complete the economic journey from Marx to the market. With 10 countries, including Poland, joining the union in May 2004, and two more, Bulgaria and Romania, following in 2007, the union expanded to 27 states, with its eastern frontier moving from the Baltic to the Black Sea.