Collar insignia

Collar insignia was what Runcible termed the distinguishing feature of the Time Lords' ceremonial robes, which bore the colours of their Chapter. (TV: The Deadly Assassin)

By the fall of Gallifrey, the collar insignia of High Council was all gold. (TV: The End of Time) Rassilon himself wore collar insignia in his post-Time War incarnation. (TV: Hell Bent)