John Lloyd (in-universe)

According to the Doctor's Five Hundred Year Diary, John Lloyd was a writer, and was not the professional tennis player of the same name.

Biography
Lloyd was hired by Douglas Adams in 1978 to provide additional scripting for the Radio 4 series The Hitchhiker's Guide to the Galaxy. When Adams became script editor for Doctor Who, Lloyd submitted a story treatment to the BBC called The Doomsday Contract - however, while Lloyd redrafted the script many times, it was ultimately never produced, in part due to Lloyd's interests shifting to spearheading Blackadder, Spitting Image, and Not the Nine O'Clock News. Forty three years later, Big Finish adapted the story into a "full cast audio version", with help from Nev Fountain, which was highly successful across Mutter's Spiral. (WC: Tom Baker stars in John Lloyd's lost Doctor Who adventure, The Doomsday Contract)

Behind the scenes
This is an in-universe version of the writer John Lloyd, who wrote The Doomsday Contract in the real world.