The gatekeepers - ie secretaries and PAs - may pride themselves on their ability to shield their bosses from annoying and time-wasting calls, but there are limits.
One Clifford Chance secretary has become something of a legend in the industry for her dogged determination to impose a blanket ban on anyone getting through.
"Who are you and what do you want?" may be reasonable enough enquiries, but perhaps her enthusiasm was getting slightly out of hand recently when she refused to put another partner through to the great man.
"He's busy," came the response.
"Well, it's very important, please interrupt him," came the reply.