Europol 'stopped three Welsh paedophile rings this year'
Three Welsh child sexual exploitation networks have been stopped this year by the European Union's law enforcement agency, its director has said.
But Europol's Rob Wainwright warned access to its intelligence and security to crack such cases would be put at risk if Britain left the EU.
He said it would become a second tier member like Norway and Iceland without access to Europol's database.
But a former UK government minister dismissed the concern.
Speaking to the BBC's Sunday Politics Wales, Mr Wainwright said: "On child sexual exploitation we've had some great success dismantling the criminal networks.... operating online."
He said Europol had co-ordinated 18 operations that involved the UK this year to close down child sexual exploitation networks - "three of those started in Wales".
Mr Wainwright was sure that Britain would negotiate access to some Europol systems, which he said allow police forces to share information, if it chose to leave the European Union.
But he added: "I can tell you in the case of Europol it would become a second tier member like Norway and Iceland is at the moment. It wouldn't have access to our database.
"So you're putting at risk I think or at least giving some uncertainty about whether you can continue to have these systems you're currently relying on."
But former Wales Office minister and intelligence officer Rod Richards said: "When it comes to accessing information, Britain, the US, Canada, Australia and New Zealand are in the premier division of gathering top secret codeword intelligence.
"The rest of Europe is not in the same league as us at all.
"So they wouldn't really want to make it difficult for us because they'd be making it difficult for the Americans and the other members of the agreement that we have to share and work with each other's intelligence."
- Watch Sunday Politics Wales on BBC One Wales at 11:35 BST, on 5 June.