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).
False titles of nobility
The British peerage encompasses the titles of baron, viscount, earl, marquess and duke. All of these titleholders, save dukes, are known by the honorific "Lord" (in Scotland the lowest rank in the peerage is "Lord (of Parliament)" rather than "Baron"). No peerage is capable of being sold, as such a transaction would be in breach of the Honours (Prevention of Abuses) Act 1925. The British embassy in the United States informs that "the sale of British titles is prohibited".