Turkey and EU agree outline of 'one in, one out' deal over Syria refugee crisis

European leaders say they have reached the outlines for a possible deal with Ankara to return thousands of refugees to Turkey and are hopeful a full agreement can be reached at a summit next week. Turkey’s prime minister, Ahmet Davutoğlu, outlined proposals early on Tuesday morning to resettle one Syrian refugee in Europe for every Syrian returned to Turkey from the Greek islands.

After 12 hours of talks in Brussels, the German chancellor, Angela Merkel, described the one in, one out proposal as “a breakthrough” that would deter refugees from making the perilous sea crossing to Greece, but said Europe needed more time to agree final details.

EU leaders will aim to seal the deal with Turkey at another summit on 17-18 March.

The Turkish proposals, which had been agreed with Merkel and the Dutch prime minister, Mark Rutte, on the eve of the summit, came as a surprise to other EU leaders. One said EU officials were left scrambling to find out if it was “legally and logistically possible”, while another diplomat said it was “naive” to think that such a complex plan could be agreed so quickly.

David Cameron said the proposal to return all refugees who make it across the Aegean Sea to Greece could provide the basis of a settlement that would finally close the refugee trail through the Balkans.

“It has been a long and difficult evening but I think we do have the basis for a breakthrough which is the possibility that, in future, all refugees who arrive in Greece will be returned to Turkey,” the UK prime minister said. “That would, if implemented, break the business model of the people smugglers and end the link between getting in a boat and getting settlement in Europe. That is something that I have been arguing for for a year and I think this is significant but only if it is fully implemented and that’s what needs to happen next.”

Following the summit, the European Union chief, Donald Tusk, said: “the days of irregular migration to Europe are over”.

Human rights groups say returning asylum seekers from Greece to Turkey would be illegal, but the EU is desperate to reduce the flow of migrants and refugees coming to Europe.

The German chancellor gave a strong signal that she supported doubling aid for Syrian refugees in Turkey, as the EU bargained with Ankara to do more to stop migrants and refugees arriving on Greek shores. EU leaders have been asked to provide €6bn (£4.6bn) over three years, twice the €3bn offered last November. Merkel said an extra €3bn would be needed, but more time was needed to agree the details.

Turkey has given shelter to almost 3 million refugees, while almost 363,000 Syrians claimed asylum in Europe last year. Up to 2,000 refugees are arriving on Greek shores every day, many from Syria, as well as Iraq and Afghanistan.

Davutoğlu promised to tackle people-smuggling, saying: “With these new proposals, we aim to rescue refugees, discourage those who misuse and exploit their situation and find a new era in Turkey-EU relations.”