https://en.wikipedia.org/wiki/Academic_dress_of_the_University_of_Cambridge
Doctors in Cambridge have two forms of academic dress: undress and full dress (or scarlet).Scarlet is worn on formal college and university occasions, and so-called Scarlet Days (see below).. The undress gown or black gown is similar to the MA gown (for PhD, MD, VetMD, BusD, EngD, EdD, LittD, ScD and in practice DD) or is a 'lay-type' gown similar to that worn by …