Would the loss of every publicly known member of the royal family make Britain a republic?
Short answerIt would not automatically exhaust the succession, and replacing the monarchy would require a separate decision about the head of state.
NotesA succession crisis depends on which relatives remain eligible, rather than simply which members of the royal family are widely recognized. Some people in the line of succession have little public profile, while prominent relatives can be much further down it. Abolishing the monarchy would raise a separate constitutional question about who becomes head of state. The alternatives considered are giving that function to the prime minister or establishing a separate elected president. The argument for institutional continuity rests on those replacement questions as well as the availability of a successor.