An anonymous reader writes The Telegraph reports, "GCHQ has lost track of some of the most dangerous crime lords and has had to abort surveillance on others after Edward Snowden revealed their tactics ... The spy agency has suffered "significant" damage in its ability to monitor and capture serious organized criminals following the exposes by the former CIA contractor. Intelligence officers are now blind to more than a quarter of the activities of the UK's most harmful crime gangs after they changed their communications methods in the wake of the Snowden leaks. One major drug smuggling gang has been able to continue flooding the UK with Class A narcotics unimpeded for the last year after changing their operations. More intense tracking of others has either been abandoned or not started because of fears the tactics are now too easy to spot and will force the criminals to "go dark" and be lost sight of completely."