More power?
Once again, it comes out, after the fact, that the asshat that carried out this killing spree was on the security services' radar and they hadn't followed it through. In this case, he was discounted as a nobody. For the 9/11 attacks, they had recordings of them planning the crime but not enough people to listen to them in time. So yes, adding more hay to the haystack without more farm hands is really going to help us.
Do the security services need more surveillance powers? I would say not. They could do with adequate staffing levels and a size nine up the backside to use the information from the powers they already have properly rather than just hoarding more. Give me more police on the street any day.