Europol's reports do not provide a breakdown of the proportion of attacks that have been completed or the type of damage inflicted. According to these data the vast majority of terrorist attacks in the EU between 2006 and 2013 are affiliated with ethno-national or separatist motives, followed by left-wing attacks and those that are registered as 'unspecified'. A significant number of terror attacks are motivated religiously or associated with right-wing groups. However, among those arrested on terror-related crimes most are religiously motivated and form the largest group, followed by separatist related terror suspects.

In 2015, a total of 211 completed, failed, or foiled terrorist attacks were reported by EU states, resulting in 151 fatalities (of which 148 were in France, with 130 of them occurring during the November 2015 Paris attacks) and over 360 people injured. As in previous years, separatist attacks accounted for the largest proportion (65), followed by jihadist attacks (17). The latter, however, caused the largest number of fatalities (150) and injuries (250). The United Kingdom reported the largest number of attacks (103), but did not provide statistics on suspected affiliation.[10] Tackling jihadist terrorism threats has become an over-riding priority for security services, although many commentators express concerns that the risk of far-right terrorism is currently being underestimated.[11]

In 2017, British intelligence MI5 said that Northern Ireland is the most concentrated area of terrorist activity "probably anywhere in Europe", with weekly threats from dissident Irish republicans.[12]