That is precisely the question which [url=http://www.theregister.co.uk]The Register[/url] asks in a piece of the same name:
The Register[/url]]
Is Europe's war on Islamist terror running out of terrorists?
The terror threat to Europe - Islamist or otherwise - may not be all it's cracked up to be, statistics published by Europol this week indicate. Europol, a criminal intelligence support service for European law enforcement agencies, maintains that the Islamist terror threat remains high despite a 22 per cent drop in arrest numbers, but as was the case with last year's report, very few actual incidents of, or attempts at, Islamist terror attacks were reported.
And then onto the meat of the article:
...There were four Islamist attacks in total, and two of these were in the UK. These however were the flaming muppet attacks in London and Glasgow, which you could reasonably class as the same incident...
And then it goes on talking about the figures, what they mean year on year, what the proportions are and how the UK figures are distorting the larger picture (which is that most terror related incidents and threats in Europe are NOT about Muslims - or as it puts it: "Europe's war on terror is largely a French and Spanish matter, related to crackdowns on Basque and Corsican groups.").
An interesting read.
