Yellesh Mercado

 was the premier of Malite.

Prior to the Dalek invasion of Malite, the Seventh Doctor and Ace visited the planet to warn them of the impending invasion. Mercado heeded the Doctor's advice and prepared his planet, which was able to hold out against the Daleks longer than any other planet had. However, Mercado soon had the Doctor arrested for treason, to hide the fact that he himself was working for the Daleks. (PROSE: Private Investigations)