again, no mention of IRA.
"Killers Michael Adebolajo and Michael Adebowale were both known to MI5 but were classed as fringe figures who did not merit full scale monitoring.

Express.co.uk quoted Barrett, as saying that it is incredibly hard to find the signals, as to when a person who expresses radical views, flips over to become a violent extremist.

Lord Blair, former Metropolitan Police Commissioner, said there were "thousands and thousands of people who listen to Islamic extremists". MI5 and MI6 must go after the most dangerous suspects who travel abroad for terrorist training, he added.

Lord Blair said the Security Service (MI5) has limited resources, and must prioritise people who are most likely to move from being interested in violent extremism to carrying it out. He said even if they have the resources to do it, they have to have a very high level of suspicion to put surveillance on them.

There are believed to be at least 3,000 people on MI5's database of extremist suspects."

http://www.business-standard.com/article/news-ani/ex-mi6-chief-says-it-s-incredibly-hard-to-stop-terror-attacks-113052600467_1.h