"Lawful interception" and illegal eavesdropping.

IEEE Spectrum has a good, long article (see especially Sidebar 4 at the end) on the Greek cellphone eavesdropping scandal. Enough bizarre elements for a good thriller novel or caper movie.

However, there is also a major technical and policy point:
The eavesdropping relied on "lawful intercept" software that had been built into the switch by the manufacturer--even though that law-enforcement capability was not being used by Greek law enforcement, and in fact had not even been enabled by the phone company.

Matt Blaze has a good post, referring to past predictions that CALEA would make telecommunications more vulnerable to eavesdropping. Steve Bellovin's post contains related comments and additional useful links.