Usurius
From Tardis Wiki, the free Doctor Who reference
Usurius was the home planet of the Usurians and the headquarters of the Company. (TV: The Sun Makers [+]Loading...["The Sun Makers (TV story)"]) A Physical Temporal Nexus was found on the planet. (PROSE: The Spear of Destiny [+]Loading...["The Spear of Destiny (short story)"])
Behind the scenes
The name is a pun on the term "usurious" which describes unusually high or unfair interest rates.