Terrorists are using the migration crisis to enter Europe and plot atrocities across the continent, the European Union’s own border agency has admitted.

In a report which lays bare the concerns about the EU’s porous borders, Frontex conceded that it does not know the true number of migrants who have crossed into the continent and has no way of tracking them.

Frontex said that EU member states had reported a record 1.82 million illegal border crossings last year, six times higher than the previous record set in 2014.