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).
Peerage of Ireland
In the following table, each peer is listed only by his or her highest Irish title, showing higher or equal titles in the other peerages. Those peers who are known by a higher title in one of the other peerages are listed in "italics".