ONCE again, the Aegean islands are witness to some of the most desperate people on earth scrambling to enter the EU.

Thousands of mostly Syrian refugees are being encouraged by Turkey’s President Erdogan to cross into Greece.

But the Greeks are having none of it, with their coastguard shooting into the sea around migrant boats, soldiers using tear-gas at border crossings and local vigilantes attacking charity workers.

Of course, as is always the case in the region, there’s more to Turkey’s reprehensible behaviour than meets the eye.

It is, in effect, blackmail, as Erdogan attempts to persuade Europe to back his violation of sovereign Syria.

Back me and I’ll keep the border secured, he says.

While there’s no doubt the west has no affection for Syria’s Assad, neither does it have the will to support Turkey, a NATO member which backs some of the most hard-line Islamists in the region.

To date, Syrian refugees have found safe haven in Turkey, funded by six billion euros from the EU.

For the reason I have explained, that is clearly not working any longer and this trickle of refugees is likely to turn into a flood.

In an attempt to counter it, the EU this week has pledged 700 million euros to enable the Greeks to act as a ‘migrant shield’.

The Greeks are clearly not impressed, claiming, fairly, that the EU has failed to persuade all its member countries to take their share of Syrian migrants.

Meanwhile, Greece’s ability to police its – and the EU’s – external border will only last as long as the funds.

This potential mass exodus from Turkey certainly proves one thing: strong borders are essential.

The EU’s open-door policy has been misconceived from the start and the chickens are coming home to roost.