A British aristocrat, Sir Lachlan Campbell, 6th Baronet, also claims the titles. He is a descendant of Sir Guy Campbell, 1st Baronet, grandson of John Campbell, son of the Honourable Colin Campbell, the son of first Earl by his second marriage to Lady Mary Campbell. Sir Lachlan however, is apparently unable to succeed because his ancestor John Campbell was illegitimate (see Campbell baronets of St Cross Mede, for further history of this branch of the family).
https://en.wikipedia.org/wiki/Earl_of_Breadalbane_and_Holland