Reporting on the claim that Kofi Annan's office was bugged, the Daily
Telegraph on Friday had an article by someone called Michael Smith whom
it describes as someone who "worked with GCHQ during the Cold War" (and
in a footnote as the author of "The Spying Game").   Mr Smith made the
following claim:

"As long as it was simply switched on, a mobile telephone on Mr Annan's
desk could be used to listen in to anything he was saying to anyone
else. Mobile telephones communicate continuously with their control
stations over a frequency that is quite separate from the one used to
talk on. Anyone who has details of the frequencies and codes in use can
listen in to what is being said in the immediate vicinity of any
telephone on the network.  Intelligence services such as GCHQ and NSA do
not even need to obtain the frequencies and codes from the network
provider, they can bypass the main network to take complete control of
any mobile telephone".  (Copyright Daily Telegraph, this is a brief
extract for the purposes of comment).

There is a certain plausibility in this claim, as it is well known that
the Post Office (and their successor BT) were happy to add circuits (and
no doubt now software) to their telephone exchanges to make it easy to
tap lines, with the security services picking up the bill.  But to get
the access to a mobile phone as claimed here would need a secret
back-door in the firmware of each phone, which requires the co-operation
of all the mobile phone manufacturers in North America, Europe, and the
Far East.  This seems a bit less plausible on political grounds at
least, and would be hard to keep secret (except that, if true, it no
longer is secret).  Maybe other people with more expertise in these
things can comment on the technical feasibility of the arrangements
described above.

While I'm no expert on mobile phones, I do know a bit about the laws of
physics, and there is no getting away from the fact that any mobile
phone which is transmitting a continuous audio stream for any length of
time would run its battery down much more rapidly than usual:  as we all
know "talk time" is much shorter than "standby time".  This would make
it hard to implement such a facility without arousing suspicion.

On the other hand, maybe that explains why my phone runs down so quickly
now: I though it was just an old battery which needed to be replaced.
Paranoid, Moi?