He is second in the line of succession , behind his father, to the thrones of sixteen independent sovereign states known as the Commonwealth realms : the United Kingdom , Canada , Australia , New Zealand , Jamaica , Barbados , The Bahamas , Grenada , Papua New Guinea , the Solomon Islands , Tuvalu , Saint Lucia , Saint Vincent and the Grenadines , Belize , Antigua and Barbuda , and Saint Kitts and Nevis .