Alexander Montagu, the oldest son of the 12th Duke, succeeded his father as the 13th Duke in July 2002; a British and Australian citizen who lives in the United States, he had been known by the courtesy title of the heir apparent, Viscount Mandeville, since his father's succession to the peerage in 1985. He has not taken the required action to be included on the Roll of the Peerage, which was created two years after his succession in 2004; while this doesn't change his status as a duke itself, which is legally established by the letters patent, inclusion in the roll is since 2004 a requirement to have his title included in his passport. Under the provisions of the 2004 royal warrant he may register with the roll at any time.
