They know where you live

Tulkinghorn has learned that the paranoia that pervades the legal world may not be totally unjustified. One US firm in London is presided over by a managing partner who formerly worked for the FBI. Not only was he responsible for providing the director with reports on counter-terrorism and espionage, this man had to read all transcripts from wiretaps and other bugging equipment.
To make matters worse, the gentleman in question once knew of an information-gathering exercise taking place within his own building. Every evening, he would greet the subject in a cheery neighbourly fashion, but come morning, he was at his desk browsing through said neighbour's conversations.
So, if you are at a US firm in London, maybe it is time to be a little more discreet on the telephone.