They knew that somebody was going to be walking down whitehall carrying weapons of some sort, and they were able to intercept this individual before he got to 10 downing street. he wouldn't have gotten very far, but nevertheless, he was wrestled to the ground and laid it became a court case. some of this they know about in advance to stop every now and then come things that frighten them are the plots that they don't know about, the so—called loan wealth attacks, where it's one person who is perhaps inspired by something they have seen online. this isn't restricted to isis or jihadist extrem...