She looks fairly healthy for a woman in her 90s. She could outlive Prince Charles with her longevity and deny him the kingship. And would Prince William get the crown instead if she decides to retire?
http://news.yahoo.com/queen-elizabeth-ii-set-become-longest-reigning-uk-071442845.html http://news.yahoo.com/queen-elizabeth-ii-set-become-longest-reigning-uk-071442845.html