Okdel L'da (PROSE: The Scales of Injustice) was the leader of a Silurian tribe who went into hibernation beneath Wenley Moor. Unlike most of his kind, Okdel was fond of mammals. (PROSE: Doctor Who and the Cave-Monsters)
Along with Morka, Bokka K'to and several other Silurians, Okdel awoke in the 20th century. He had developed a relationship with the human Dr John Quinn. The Third Doctor convinced him that the Silurians could share Earth peacefully with mankind. When he realised that Morka was trying to wipe out humanity with a virus, he freed the Doctor and gave him the means to find an antidote.