The letter written by the chairman of King Edward VII's Hospital, Lord Glenarthur, to Max Moore-Wilton, chairman of 2day FM's parent company Southern Cross Austereo.
"I am writing to protest in the strongest possible terms about the hoax call made from your radio station, 2Day FM, to this hospital last Tuesday.
"King Edward VII's Hospital cares for sick people, and it was extremely foolish of your presenters even to consider trying to lie their way through to one of our patients, let alone actually make the call.
"Then to discover that, not only had this happened, but that the call had been pre-recorded and the decision to transmit approved by your station's management, was truly appalling.
"The immediate consequence of these premeditated and ill-considered actions was the humiliation of two dedicated and caring nurses who were simply doing their job tending to their patients.
"The longer term consequence has been reported around the world and is, frankly, tragic beyond words.
"I appreciate that you cannot undo the damage which has been done but I would urge you to take steps to ensure that such an incident could never be repeated."