So, ‘all members of the Royal Family’ are ranked as follows by the Palace: The Queen; Prince Philip; Prince of Wales; Duchess of Cornwall; Prince William; Prince Harry; the Duke of York; the Duchess of Cambridge; the Earl of Wessex; the Countess of Wessex; the Princess Royal; the Duke of Gloucester; the Duchess of Gloucester; the Duke of Kent; the Duchess of Kent; Princess Alexandra.
I found this interesting - why is Kate slotted in between the Duke of York and the Earl of Wessex?
That is not their ranking; that is merely in what order they are listed in the official diary. Similarly, Prince William is listed above his uncles.
There are two orders of precedence - an official one and a private one. The Official Precedence (ranking for official events) is determined by law and traditions, whereas the Private Precedence (ranking for private events) is at the will of the Sovereign.
The Official Ranking For Men:
- The Duke of Edinburgh (except, where provided by Parliament, he is outranked by The Prince of Wales)
- The Prince of Wales (except, where provided by Parliament, he outranks his father)
- The Duke of York
- The Earl of Wessex
- The Duke of Cambridge
- Prince Harry
- James, Viscount Severn
- Peter Phillips
- Viscount Linley
- Duke of Gloucester
- Duke of Kent
- Prince Michael of Kent
The Official Ranking For Women:
- The Queen (the Sovereign)
- The Duchess of Cornwall (wife of the Heir Apparent)
- The Countess of Wessex (wife of the Sovereign's younger son)
- The Princess Royal (the Sovereign's daughter)
- The Duchess of Cambridge (the wife of the Sovereign's grandson)
- Autumn Phillips (the wife of the Sovereign's grandson)
- Princess Beatrice (the Sovereign's granddaughter)
- Princess Eugenie (the Sovereign's granddaughter)
- Lady Louise (the Sovereign's granddaughter)
- Zara Phillips (the Sovereign's granddaughter)
- Viscountess Linley (the wife of the Sovereign's nephew)
- Lady Sarah Chatto (the Sovereign's niece)
- The Duchess of Gloucester (the wife of the Sovereign's cousin)
- The Duchess of Kent (the wife of the Sovereign's cousin)
- Princess Michael of Kent (the wife of the Sovereign's cousin)
- Patricia, Countess of Harewood (the wife of the Sovereign's cousin)
- Princess Alexandra (the Sovereign's cousin)
The Private Ranking For Men 1: *
- The Duke of Edinburgh (except, where provided by Parliament, he is outranked by The Prince of Wales)
- The Prince of Wales (except, where provided by Parliament, he outranks his father)
- The Duke of York
- The Earl of Wessex
- The Duke of Cambridge
- Prince Harry
The Private Ranking For Men 2: *
- The Duke of Edinburgh (except, where provided by Parliament, he is outranked by The Prince of Wales)
- The Prince of Wales (except, where provided by Parliament, he outranks his father)
- The Duke of Cambridge
- The Duke of York
- The Earl of Wessex
- Prince Harry
The Private Ranking For Women 1: **
- The Queen
- The Princess Royal
- Princess Beatrice
- Princess Eugenie
- Lady Louise (assuming she is counted as a Royal Princess, which she legally is)
- Princess Alexandra
- The Duchess of Cornwall
- The Duchess of Cambridge
- The Countess of Wessex
The Private Ranking For Women 2: **
- The Queen
- The Duchess of Cornwall
- The Duchess of Cambridge
- The Countess of Wessex
- The Princess Royal
- The Duchess of Gloucester
- The Duchess of Kent
- Princess Alexandra
* The official website lists the Duke of Cambridge above his uncles, which suggests he has precedence over them. However, unlike the private precedence for women, no announcement or edict of any kind has ever been issued, so it might well be a mistake, or just listing for convenience.
** The official website is a bit confusing in that respect; although in the private precedence Princesses by birth (Anne, Beatrice, Eugenie, Alexandra and possibly, Lady Louise) should be ahead of everyone else, the Duchess of Cornwall is still
listed immediately after the Queen, followed not by the Countess of Wessex - the wife of the Sovereign's younger son - but the Duchess of Cambridge.
In short, I doubt even the Court knows who is after whom.