Dukes in the United Kingdom
Duke, in the United Kingdom, is the highest-ranking hereditary title in all four peerages of the British Isles. A duke thus outranks all other holders of titles of nobility (marquess, earl, viscount and baron).
Order of precedence in England and Wales
Peers and their families make up a large part of these tables. It is possible for a peer to hold more than one title of nobility, and these may belong to different ranks and peerages. A peer derives his precedence from his highest-ranking title; peeresses derive their precedence in the same way, whether they hold their highest-ranking title in their own right or by marriage. The ranks in the tables refer to peers rather than titles: if exceptions are named for a rank, these do not include peers of a higher rank (or any peers at all, in the case of baronets). No exceptions are named for most categories, owing to their large size.