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).
Aristocracy (class)
In the United Kingdom, members of the highest echelon of the aristocracy, the hereditary peers were, until 1999, members of the House of Lords—the upper house of the legislature, the Parliament of the United Kingdom. In 1999, most ceased to be members. However, the Duke of Norfolk, who always serves as Earl Marshal, the hereditary peer who serves as Lord Great Chamberlain (currently the Marquess of Cholmondeley), and a further 90 Representative Hereditary Peers elected by the Hereditary Peers retained membership. Since 1958, non-hereditary "life peers" have been created, who are automatically members of the House of Lords for life with the right to be known by their title. For example, John Gummer became (The Rt Hon.) Lord Deben.