Scarlet

Members of the Prydonian Chapter were distinguished from the other Chapters by their scarlet and orange robes. (TV: The Deadly Assassin)

Gwen Cooper wore a scarlet shirt throughout the 21st century Dalek invasion. (TV: The Stolen Earth, Journey's End)

Romana wore a scarlet frock coat with her ivory stock tie, her white shirt, her gold waistcoat, her beige jodhpur s, and her brown boots. (TV: The Horns of Nimon)

Clara Oswald wore a scarlet dress with a black collar and a short skirt. (TV: Journey to the Centre of the TARDIS)

Martha Jones wore a scarlet tank top. (TV: 42)

The Master wore a scarlet t-shirt under a black hoody. (TV: The End of Time)