Couple of minor problems
(1) Gathering data is not enough. Analysing it and acting on the results is also required. Police numbers are being cut due to "austerity" so who is going to use this data?
I've lost count of the number of terroirists who have turned out to be on watch lists and "under surveillance" who still manage to attack the public unhindered. That includes those who have been reported by their own families as a risk.
(2) BGP leaks. Apparently this proposal will make analysis of redirected traffic trivial when a "misconfiguration" of a minor ISP can send all your network traffic through another country.