Fifth Corsair

The Fifth Corsair once got drunk with the Doctor and woke up with him either in jail or the vaults of the Bank of England. She had the smallest Ouroboros tattoo of any of the Corsair's incarnations, with it being the size of a ten pence piece and located on her upper thigh. (PROSE: Eleven Things You Probably Didn't Know About the Corsair)

Behind the scenes
While the text of Eleven Things You Probably Didn't Know About the Corsair states that her ouroboros tattoo was the size of a ten pence piece, the accompanying artwork is at odds with it, as it depicts the tattoo being much larger.