Fears in Europe are growing that Turkey’s increasingly authoritarian Islamist president could renew demands for easy access to Europe for 75 million Turks, while threatening to scrap a deal which eased the migrant crisis last year.

European diplomats expect Recep Tayyip Erdoğan to consolidate his new executive powers by picking political battles with the EU, The Times reports. They fear he will abandon ambitions to join the European Union (EU), dropping judicial and democratic reforms demanded by the bloc, as well as issuing an ultimatum on visa-free travel for Turks.

Yesterday, the president slammed the EU for keeping Turkey “waiting” and said he could call a referendum on the country’s bid to join the bloc.

Mr. Erdoğan narrowly won a constitutional referendum on Sunday, meaning he will be able to act without the approval of his parliament and stay in power for longer.

The promise of easy access to the EU for Turks was a principal part of a deal, made in March last year, to stop boats crossing to Greece and requiring Turkey to accept the return of some “irregular migrants”.

Soon after the deal was signed, Turkey began threatening to scrap it and “open the gates” to a new migrant wave into Europe unless the president’s demands were met.

The Turkish government has renewed such threats in recent days, and a new ultimatum is expected imminently. Last Friday, Mevlüt Çavuşoğlu, the Turkish foreign minister, warned the deal could be torn up without free movement for Turks.

Ömer Çelik, the Turkish minister for EU affairs, told The Times the EU should weaken its demands for reform in Turkey “while granting visa exemption to Turkey”.

“If we get a negative response from the EU we have the right to re-evaluate and suspend all of these agreements,” he added.

In the hours after the vote, Mr. Erdoğan said he wanted to bring back the death penalty, which would automatically end talks about visas. Jean-Claude Juncker, president of the European Commission, has said that the issue is a “red line” for the EU.

Gianni Pittella, the Italian leader of the socialists in the European Parliament, said that his bloc of MEPs would hold talks on whether to veto visa-free travel for Turks next week.

“We’ve always been very reluctant to ensure a visa-free regime to Turkey as, in our opinion, Ankara does not match the democratic criteria,” he said. “Now after the referendum our concerns are even bigger.”

A senior Greek official told The Times that the country’s military has already drawn up emergency plans to cope with a new migrant crisis.