The European Union has pledged over three-quarters of a billion dollars to help Greece cope with a surge in the number of migrants trying to cross into the country from Turkey, as the bloc fears a repeat of the 2015 crisis. Greece has closed down the land border and ramped up security across the frontier. The EU says Ankara is fully to blame for the crisis, as tens of thousands of migrants remain camped out along the border. Henry Ridgwell reports.