Fresh concerns have been raised about Europe's ability to protect its borders after asylum seekers managed to enter the Schengen zone undetected, and fly on fake ID cards. Photo: GETTY

Fresh concerns have been raised about Europe's ability to protect its borders after asylum seekers managed to enter the Schengen zone undetected, and fly on fake ID cards.

Syrian, Iraqi and other nationals are walking across Turkey's land border with Greece, where they are buying fraudulent documents which have been accepted on commercial flights to western Europe.

By doing so they are getting around a deal the EU agreed with Turkey, that Turkey would take back illegal migrants arriving on Greek shores from Turkey.

Europol, the EU law enforcement agency, last night admitted the problem was much wider. The ease with which the asylum-seekers made the journey raises serious questions about the EU's ability to protect external perimeters at a time when Isil is looking for ways to send fighters to European cities.

One Syrian man in his 30s, who wished to use only his first name, Ahmed, told how he paid €1,000 to a smuggler in Istanbul to help him reach Greece.

"If you have the money, there is a luxury way," Ahmed said. "We travelled by car from Istanbul to Edirne [in north-west Turkey], then we walked for an hour to the river [Meric], and from there we got a boat which just took two minutes."

He crossed illegally into Greece, negotiating his way around guards at one of the world's busiest border gates with the help of the smuggler.

He took a taxi and then a coach to Athens. Once in Athens, Ahmed paid another smuggler €6,000 for a fake Greek ID card. The card bore his photograph but the name of a real Greek citizen.

With it he managed to buy a plane ticket to Amsterdam. Under the Schengen Agreement, people are able to travel around EU member states without showing a passport.

During the height of the migrant crisis in the summer of 2015, Greek authorities reported finding up to 200 forged passports and IDs a day at Athens airport.

But the trade was thought to have tailed off after the EU and Turkey signed a deal under which Ankara stopped asylum seekers from crossing by sea to the Greek islands in return for €3bn in aid.

Under the Dublin Regulation, asylum seekers should be sent back to the first Schengen zone country they reach.

Telegraph.co.uk