In 1968–1969, Sherwin began to take a greater role in the producing side of "Doctor Who", and after the serial "The Mind Robber", he became the unofficial assistant producer for the next three serials, with Terrance Dicks succeeding him as script editor. On "The Space Pirates", Sherwin briefly resumed his old role as script editor, while Dicks was busy writing the epic 10-part season finale "The War Games" with Malcolm Hulke. Dicks credited Sherwin with the creation of the Time Lords, who were introduced in "The War Games".