UKIP Home Affairs spokeswoman Jane Collins has responded to claims from Europol chief Rob Wainwright, saying he is "still fighting for Project Fear."
Mr Wainwright, who became involved in the Remain campaign for the EU referendum last year, told Sky News:
“I have seen how threats of terrorism and organised crime have become more global and the need for greater international police cooperation is absolutely essential to keep us safe.
"Mechanisms such as Europol provide an important part of the way in which the law enforcement community in Britain and other countries around Europe can discharge those responsibilities."
But Ms Collins blasted the comments, saying:
"I am sure that the UK government will secure some kind of intelligence sharing but what people should be aware is that the UK is part of a superior organisation called Five Eyes, a multilateral agreement with Australia, Canada, New Zealand and the USA where we share signals intelligence.
"The fact is we give Europol more intelligence than they give us and they are not invited to be part of 5 eyes because of concerns about leaking.
"And what is more important is a properly funded security services and military and secure borders. We will be a more secure nation if we don't have free movement of terrorists and weapons which Schengen has brought right to our doorstep.
"Under no circumstances must we remain part of the European Arrest Warrant which is the death knell for the foundation of UK law, Habeas Corpus, and the primacy of innocent until proven guilty."