A long time ago in a galaxy far, far away, or alternatively a few years ago on the show, it became common for listeners with relevant qualifications to the subject they were corresponding about to state such qualifications at the end of their letters, emails and texts. This was soon misappropriated by the general public to include less than relevant attainments, such as finishing positions in egg and spoon races, swimming certifications, and being a milk monitor.
This started with Mark Kermode's review of the film March Of The Penguins and specifically his phrase "how did the fish get out of the water?" A week after the review, a listener emailed in, annoyed that this phrase seemed to side with the American creationist interpretation of the film, which took it to be evidence of Intelligent Design. To make his point, the emailer contrasted his PhD in Zoology with Mark's PhD in Horror Fiction. A debate ensued during the show with various theology PhDs weighing in. This is what sparked the qualifications tradition as listeners continued to add their increasingly amusing achievements at the end of their correspondence.
Mark would later seek the most intelligent person to have enjoyed Sex And The City (with the “enjoyed” being crucial - after all, Mark was clearly the most intelligent person to have seen it) and there have been some who have assumed this was the origin of people sending their qualifications. But it isn't.