Rob Wainwright says a Brexit could mean security challenges for Britain
The head of Europol has said there is a growing threat of a spectacular terror attack in Europe.
Rob Wainwright, who is British and a former MI5 officer, said the UK would face significant security challenges if it left the European Union.
He has been the director of the agency responsible for the coordination of the European Union's law enforcement since 2009.
Speaking from the organisation's headquarters in The Netherlands, Mr Wainwright was frank about the challenges following last November's Paris attacks.
"I think it is likely that we will have another attack. We are working, of course, around the clock to prevent that from happening but this is a very, very serious threat".
"It's certainly the highest terrorist threat we have faced for over 10 years and we need to up our game as a collective counter terrorist community to make sure we can protect our citizens from this".
The Paris attacks exposed failings in Europe's ability to coordinate and share intelligence on known terror suspects.
The attack mastermind, Abdelhamid Abaoud, was able to pass freely through Europe to Syria and back without being apprehended despite being the subject of an international arrest warrant.
One of the attackers, Saleh Abdeslam, was stopped by police hours after the attacks driving into Belgium. They failed to arrest him and he remains on the run.
"Since Paris I can tell you that at Europol we have seen a significant increase in the amount of intelligence that's now been shared...a determined response by the community to prevent another Paris-style attack," Mr Wainwright said.
The unprecedented migrant and refugee crisis has exposed Europe to massive challenges on two separate fronts: people trafficking and terrorism.
"Some 1.8 million migrants and refugees arrived in Europe last year putting huge pressures on our external border and [...] fuelling a serious increase in people smuggling which has become the fastest growing criminal sector now in Europe".
"There are security dimensions attached to this migration crisis, and at the same time the highest terrorist threat for 10 years, so the twin effects of that mean that we are in very uncertain times in Europe at the moment".
The attackers in Paris were Europeans, radicalised in Europe but trained in Syria. The number of people who pose a threat is huge, according to shared European intelligence. [There are] at least 5,000, we think, that have been radicalised by ISIS, very often online and have acquired conflict experience in Syria and Iraq. Many of them have since returned," Mr Wainwright said.
Against this backdrop, Mr Wainwright was happy to voice his views on the impact a 'leave' vote would have on the UK's security.
"One can expect that the arrangements [in the event of the UK leaving the EU] will be not as optimal and therefore it will be difficult for the UK to replace what it currently relies on in the EU with arrangements that would be as effective and as cost efficient as well," he said.
Europol says 2,500 operational cases were brought to its attention by British law enforcement agencies in 2015. Up to 40% of all Europol casework has what Mr Wainwright calls a 'British dimension'.
In that context, he argues that the UK's membership with the EU enhances cooperation and improves security in the UK and across the continent.
London Mayor Boris Johnson, who is campaigning for the UK to leave the EU, has suggested EU bureaucracy hampered the UK's ability to fight crime and terrorism.