A lot of high-ranking members of the Queen's staff aren't "staff" so much as they are officials with particular duties and ceremonial titles. This is the case with the Master of the Horse, a historic position that is largely ceremonial for the modern royals — but ceremony is a big part of the royal image! He formally supervises all matters related to the royal stables, although in reality, the Crown Equerry and the Royal Train Office deal with most of the position's former duties.