"If Europe cannot act together to persuade a significant majority of its citizens that it can gain control of its migratory crisis then the EU will find itself at the mercy of a populist uprising, which is already stirring," ex-MI6 chief Richard Dearlove told the BBC in an interview released on Monday.
Dearlove also warned against the European Union granting Turkey visa-free travel.
Europe has been beset by a refugee crisis, with hundreds of thousands of undocumented migrants fleeing their crisis-torn countries of origin, trying to escape violence and poverty. The majority of them come to Europe across the Aegean Sea from Turkey.
In mid-March, Brussels and Ankara agreed on a deal under which Turkey pledged to take back all undocumented migrants who arrive in the European Union through its territory in exchange for Syrian refugees accommodated in Turkey, on a one-for-one basis. In return, the 28-member bloc pledged to accelerate the Turkish EU accession bid and introduce a visa-free regime between Turkey and the Schengen area.