Commonwealth leaders are meeting at Windsor Castle, where they are set to discuss whether Prince Charles should succeed his mother Queen Elizabeth II as head of the 53-nation alliance.

The queen has headed the association of Britain and its former colonies throughout her 66-year reign, but the position is not hereditary.

The 91-year-old monarch has said she hopes her son and heir will succeed her. The decision will be taken collectively by Commonwealth heads of government, who are meeting Friday at the royal residence.

The British government has backed Charles, and Canadian Prime Minister Justin Trudeau says he agrees "very much" with the queen's wishes.

This week's Commonwealth summit has been overshadowed by a scandal over the treatment by U.K. immigration authorities of some long-term residents from the Caribbean.