Dal Karlton

Dal Karlton was chief of the Space Security Service (S.S.S.) on Earth in 4000. He assisted Mavic Chen, the Guardian of the Solar System, and was Chen's co-conspiritor in the secret alliance with the Daleks.

Profile
Loyal to Mavic Chen for as long as it suited his ambitions, Karlton was unaware of both Marc Cory's and Bret Vyon's missions to Kembel, and sent Sara Kingdom, his most ruthless and trusted agent, to stop the truth emerging. He hinted that when the opertunity emerged he would betray Chen and try to replace him. (DW: The Daleks' Master Plan)

Behind the Scenes
Placebo Effect by Gary Russell makes reference to Karlton working at S.S.S. Headquarters on Earth. This probably refers to him.