[3dbrows]

In the Royal Navy, written letters to the captain [1] have to be signed off with "I am honoured to be, Sir, your obedient servant". I remember (in 2010) people thought this was stupid and instead used something like "Yours sincerely". But this ran contrary to regulations, and it was announced that letters would be rejected if not signed properly. Time moves very slowly in the RN.

[1] There are codified degrees of formality for written communications. Formal, demi-formal, and others used more operationally. I am talking about first-tier formal letters to senior officers in this case.