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).
List of viscounts in the peerages of Britain and Ireland
This is a list of the 112 present and extant Viscounts in the Peerages of England, Scotland, Great Britain, Ireland, and the United Kingdom. Note that it does not include extant viscountcies which have become merged (either through marriage or elevation) with higher peerages and are today in use only as subsidiary titles. For a more complete list, which adds these "hidden" viscounties as well as extinct, dormant, abeyant, and forfeit ones, see List of Viscountcies.