Current order of precedence:
By (the Queen's) Order-in-Council, the Duke of Edinburgh has "place, pre-eminence and precedence" over all men in the United Kingdom—except, where provided by Parliament, Charles, Prince of Wales.
In 2005, Elizabeth II changed the order of precedence for private occasions, putting Camilla, Duchess of Cornwall, fourth in the order of precedence, after herself, Anne, Princess Royal, and Princess Alexandra, contrary to the usual position of the heir's consort. Charles' first wife, Diana, Princess of Wales, had ranked above the Princess Royal and Princess Alexandra.[1]
The Duchess of Cornwall continues to rank second in the order of precedence at official occasions, such as state dinners.
Princesses of the blood Royal, such as Princess Beatrice of York and Princess Eugenie of York, also rank above Catherine, Duchess of Cambridge, when the latter is not accompanied by her husband. When the Duchess of Cambridge is joined by the Duke, the roles are reversed with the Duchess outranking the Princesses.
The Court Circular also lists Prince William, Duke of Cambridge above his uncles, Prince Andrew, Duke of York and Prince Edward, Earl of Wessex.
There is no specific place in the order for a great-grandchild of the Sovereign (no matter how senior in the order of succession), however Prince George of Cambridge is entitled to precedence after all non-royal dukes as the eldest son of a Duke of the Blood Royal, pursuant to the unrevoked Lord Chamberlain's Order of 1520 as amended in 1595. (His sister, Princess Charlotte of Cambridge, has the equivalent position in the women's order.)[2]