Tinkety tonk old fruit, and down with the Nazis

Sign-off originally used by the Queen Mother in a letter in February 1941, quoted by a listener in correspondence in 2016 and swiftly embraced by Mark and Simon, to the extent that it became the sign-off for a trail they made advertising 5 Live.

"Tinkety tonk" on its own had previously been used in listener correspondence as far back as 2011, when Simon was rather taken with it (to the extent of using it throughout the show, much to Mark's growing exasperation), and a quick spot of Man looking up something on a computer revealed that it originated in the work of PG Wodehouse (who spelled it as "tinkerty", unlike HMQM). Whether this was where the Queen Mother took it from is unknown.