…that titles were rarely rescinded, historically, even if the Crown made a mistake, because, well, the Crown didn’t make mistakes. According to Debrett’s, “When a hereditary peer dies, and his heir wishes to prove his claim to the title, he or she must provide suitable documentary evidence to the Crown Office of the House of Lords to prove that he or she is indeed the heir to the title.”
A claim was handed from the Crown to the House of Lords, where the documentation was scrutinized by the Select Committee for Privileges, a body that guarded not only the privileges of Lords and the peers who sat in it and who got in, but also the conduct of members. Once the committee confirmed a claim, the sovereign had the final approval and only then claimant assumed the title. Once decided it was a done deal.
Someone who attempted to bring claims after the fact could petition the Crown. Ironclad evidence might theoretically cause the decision to be sent to the Committee for Privileges to investigate and be overturned, but the combined wrath of the Crown and Lords would more likely come down on the trouble maker. The Crown did not like to be caught wrong footed.
On the other hand, even if overturned, such a scandal would linger. The son of the man who retained the title might find his own claim questioned when the former duke/marquess/earl died.
This issue plays an important role in The Defiant Daughter, my work-in-progress to be published in October.