The divisive question of Turkey’s accession to the European Union is reopened on Tuesday with an appeal from 50 prominent politicians and intellectuals for the door to full membership for Ankara to be kept open.

“Starting with the European Union’s neighbours, the best way to secure peace and prosperity is to honour existing commitments to countries seeking membership and to encourage political reforms with more generous offers of economic opportunity and political co-operation,” the 50 public figures say in a statement launching a think-tank, the European Council on Foreign Relations.