Rob Wainwright, the head of the EU's policing body Europol, said 1,400 new cases of human trafficking had been opened in 2015.

"We've identified in those cases almost 30,000 suspected people smugglers at different chains, different levels of criminal syndicates.

"All of them with cross-border elements, so involving at least two countries, many of them involving multiple countries, and at different levels of scale.

"If we can make a serious inroad on that then of course it helps to ease the wider pressures involved."

Britain and Ireland are under pressure to accept more refugees as Mediterranean states and Balkan countries see thousands of new migrants arriving in an attempt to get to other EU nations, such as Germany.

Mr Wainwright said criminal activity was at a "very high" level as criminal gangs sought to exploit those fleeing the Middle East and North Africa.

He added that they were increasingly using social media to target their "victims."

Europol has set up a special cell in Sicily intended to get more specific intelligence about Mediterranean trafficking operations.

"Most of our work is concerned with what we call the secondary distribution of migrants and refugees," Mr Wainwright said.

"After they've come through the external border and as they make their journey across European countries."

UK Border Force boss Philip Duffy last month warned that trafficking gangs are trying to smuggle migrants into the UK who will then be used to commit crime.