The upsurge of migrants heading to Europe from Africa is threatening to undermine living standards and social structures in the EU, Foreign Secretary Philip Hammond has warned.
Mr Hammond said the continent could not absorb "millions" of Africans and EU laws needed to be overhauled to ensure those coming simply to find a better way of life could be returned to their own country.
He said that in many cases, migrants knew they only had to set foot in Europe for there to be little chance of them ever being forced to leave.
"We have got to be able to resolve this problem ultimately by being able to return those who are not entitled to claim asylum back to their countries of origin. That's our number one priority," he told BBC News.
His comments came after Greek prime minister Alexis Tsipras warned his country was being overwhelmed by the influx of arrivals crossing the Mediterranean.
Last month alone, almost 50,000 migrants arrived in the EU through Greece compared to a total of 41,700 in the whole of last year, according to the latest figures from Frontex, the EU border agency.