Question: Who was prime minister of the UK from 1955  to 1957 that James Stuart served as Secretary of State for?
Sentence (from "Swedish governmental line of succession"): The only case where the governmental line of succession becomes relevant is when the Prime Minister dies (upon which the person next in the line of succession serves as the head of a government "ad interim") or when the Prime Minister is on leave or for any other reason incapable of serving, but still remains in office.
Relevant evidence: No