Officers from the EU law enforcement agency, Europol, are immune from prosecution.
This isn't correct. Europol staff working on an investigation in a member state are in the same position as ordinary officers when it comes to criminal prosecution.
"UKIP have said in a promotional video that the European police force is immune from prosecution. Is this true?"
Via email, 7 April 2015
The EU's law enforcement agency labours under the unfortunately Orwellian name of 'Europol'. It's no surprise, then, that its powers are the subject of concern and speculation (although we've not been able to verify that UKIP is among those making this particular claim).
In this instance, those concerns are misplaced. Being an officer of Europol—unlike being a diplomat—doesn't guarantee immunity from criminal prosecution.
Europol, or the European Police Office, describes its job as being to "support EU law enforcement colleagues by gathering, analysing and disseminating information and coordinating operations".
It isn't a "police force" in the same sense as, say, the Met. It can't launch an investigation on its own initiative. Even when invited on a joint investigation with national police forces, its officers have no power to make arrests.
Europol is also limited in the types of crime it can handle.
Be you never so high, the law is above you
A lot of what Europol does is information sharing, rather than sending officers into member states. Nevertheless, some worry that when "operating in the UK [Europol officers] have diplomatic immunity and cannot be touched by the British judiciary", as the Daily Mail put it in 2010.
They aren't above the law. Europol staff accused of a crime while operating in the UK are in the same position as British police officers.
As the relevant EU law expresses it:
"During the operations of a joint investigation team, Europol staff shall, with respect to offences committed against or by them, be subject to the national law of the Member State of operation applicable to persons with comparable functions."
Where do claims about 'diplomatic immunity' come from, then?
The European Union has "privileges and immunities" guaranteed by the EU treaties. These rights are supposed to be those necessary for the EU to do its job. So, for instance, EU offices can't be searched or seized. (Other international organisations have very similar systems in place.)
EU officials also have protection. They are "immune from legal proceedings in respect of acts performed by them in their official capacity".
But in 2008, the EU passed a law to clarify that this immunity doesn't apply to Europol staff working on a Joint Investigation Team.
Update 25 August 2015
We clarified that we haven't been able to verify whether or not UKIP has made the claim about Europol's powers attributed to it.