Social class

Flor's mother disapproved of Flor's relationship with Margaret, as she wanted her to marry someone of higher social class, closer to their own financial standing. Flor did not understand, as they already had estates, while Margaret brought something entirely new in her life. (AUDIO: Dead and Breakfast)

Addressing humankind shortly before the Battle of Canary Wharf, Cyber-Leader One announced that their upgrade to cyber-form would remove, among other things, class. (TV: Doomsday)

The Doctor
Though the Sixth Doctor asserted that he would be considered a plebeian on his home planet, Gallifrey, (AUDIO: Cortex Fire) Engin regarded the Fourth Doctor, even as a renegade, as someone of high status. This was because he belonged to that "noble Chapter", the Prydonian Chapter. He indicated that Spandrell's duties more typically lay with "more plebian classes" than this. (TV: The Deadly Assassin)

Indeed, Robin Hood learned from Clara Oswald that, like himself, the First Doctor had been born into wealth and privilege. The Twelfth Doctor did not contest this information. (TV: Robot of Sherwood) Clara also had knowledge of the Doctor's "Prydonian privileges" prior to becoming a renegade, which had since been revoked. (TV: Death in Heaven)