Financial Times.
"Security experts argue that MI5 and the police have records on many Islamist extremists in the UK. In 2007, Jonathan Evans, former head of MI5, said there were at least 2,000 people in the UK who "pose a direct threat to national security and public safety".

However, security experts say MI5 has to constantly assess which of these might go on to plot acts of violence and therefore need to be pursued with greater intensity. "
http://www.ft.com/cms/s/0/33d814b4-c3d3-11e2-aa5b-00144feab7de.html#axzz2UPAKLP8K
What are you taking issue with Don?