Do we know anything about Mrs. Hughes's husband, Mr. Hughes?
Never married…thought this was touched on in Season 1. The "Mrs." is a title. I assume the same goes for Mrs. Patmore.
Interesting. Thank you!
The first response is correct. All cooks and all housekeepers were called "Mrs. [Surname]" by their employers, even if they were never married. An employer would address a lady's maid by the maid's last name, with no honorific (which is why the Countess of Grantham calls her maid "Baxter", or why Mrs. Levenson addressed her maid as "Reed".) Valets, grooms, chauffeurs, and butlers were also addressed by their employers by their surnames, and thus you have "Carson", "Bates", and "Branson". Maids and footmen were addressed by their first names. Downstairs, the higher-ranking servants who were called by their surnames by their employers would have an honorific added when other servants spoke to them -- and thus you have "Miss O'Brien", and "Mr. Carson". Naturally, the housekeeper and the cook would also be addressed by other servants with an honorific in front of the surname -- but if the Earl and countess are already addressing the woman in question as "Mrs. Hughes", it would be odd for the servants to change the honorific she already has to "Miss" instead.