“They feel a sense of unfairness and discrimination but maybe more importantly, they feel that those that are there to protect them, namely the police, are not,” he said.

The stigmatisation resulting from such profiling risks pushing already disenfranchised young people towards radicalisation, he warned.

Poverty in some member states is feeding racism and leading to the scapegoating of minority Muslim, Jewish and Roma groups, he says.

“I sense a growing anger. An anger that was not there in 2007-8 when I came in. And that anger we need to relate to,” he told this website.

A 2010 FRA survey found minorities are in some city neighbourhoods far more often likely to be stopped by police when compared to the predominately white residents.

Kjaerum cited the planned EU’s passenger name records (PNR) bill – under which air passenger personal details are handed to authorities – as likely to open the door to ethnic profiling.

National plans, backed by the European commission, to confiscate the travel documents of people leaving to fight in Iraq or Syria could have the same result. Policies, he says, need to be designed with fundamental rights from the outset.

The experience of Dimitri Bontinck, from Antwerp in northern Belgium, shows the complexity of the problem.

He rescued his radicalised son from the terror group in Islamic State in Syria and has since gone on to negotiate other hand-overs.

“Many (foreign fighters) are ready to come back and I know that very well because my last mission was in December,” he said.

“I’ve been five times with parents, five times, and negotiated in dialogue with Islamic State,” he added.

He said that often the children do not want to return because they fear western governments will “criminalise them and put them in jail. They are only ready to return if the ministers of justice give them political asylum.”

How to tackle the phenomenon of foreign fighters – EU citizens who choose to go and fight for IS – is one of the thorniest problems currently being dealt with by interior ministers.

In Belgium, the problem is particularly acute. It has the highest per capita rate of foreign fighters in the EU.

In Botinck’s case, his son Jeroen returned from Syria and was the key witness in a trial earlier this month which saw the head of a radical militant Islamic group - Sharia-4-Belgium - sentenced to 12 years in prison.