King Charles is not inviting his former sister-in-law the Duchess of York to his coronation, The Independent has learnt.

Sarah Ferguson, who still lives with Prince Andrew and is very close to him even though they divorced in 1996, will have to watch the 6 May celebrations at Westminster Abbey on TV.

The news follows the Duchess of Sussex’s decision to miss the coronation by staying at her home in California with Prince Archie and Princess Lilibet while Prince Harry attends alone.

The King and Queen Consort’s decision means that Fergie will not be seated next to her daughters, Beatrice and Eugenie, who are 10th and 11th in line to the throne.

The exclusion is somewhat surprising as Prince Andrew was recently invited to Windsor by the King over Easter, even though it has been made clear that the duke will be excluded from the inner workings of the royal family.

The refusal to invite the duchess will cause a debate among royal watchers, as some see her as a national treasure who has courageously overcome financial and personal problems within the royal family, while others see her as an error-prone embarrassment.

“She has been hugely supportive of Charles and Camilla and does not want this to become about her,” a friend said.

“The whole day is about the new King and the success of his reign but she has always championed the royal family and the Queen undoubtedly would have wanted her to be there.”

The Duchess and the Duke of York were married in 1986 and split up in 1992. She was then distanced from the royal family after being linked to a series of scandals.

Despite the controversies, the Queen very publicly stood by her and in the last month of her reign made a point of supporting the duchess and spending a lot of time with her, even walking together in Windsor Park.

A friend said: “The Queen found Sarah warm and loyal, almost to a fault, and also found her amusing.”

Royal commentator Ingrid Stewart told The Independent that the decision to not invite Fergie is “not a matter of personal preference but protocol”.

“Fergie has not been invited to any official royal events since her divorce. As the ex-wife she would not expect to be invited,” she said.

The duchess was known to the Queen before she was married as her father Maj Ronald Ferguson was the royal polo manager.

Even though she was not invited to stay for Christmas at Balmoral due to Prince Philip’s hostility towards her, she always stayed nearby on a cottage on the estate.

In the last few weeks she has been on a series of publicity launches for her new book, A Most Intriguing Lady, and has always gone out of her way to be gushingly supportive of the royal family – in particular the new King and Queen.

Earlier this month she told OK! magazine: “I think if you look at the King’s track record in areas like the environment, where he was decades ahead of his time, and the Prince’s Trust, it’s clear what an extraordinary man he is. How fortunate we are to have him on the throne.”

Buckingham Palace revealed on Wednesday that Meghan would not accept her invitation and it is thought that Archie’s fourth birthday on the same date might have played a factor in the decision.

Meghan’s absence leaves a space in the seating at the coronation which could easily be filled should the King reverse his decision.

There have already been rows over who has and has not been invited to the ceremony, with places tight, and cabinet ministers not allowed to bring a plus one.

Lord Mowbray, Segrave and Stourton, the oldest English barony, has been invited but other ancient titles have found themselves banished to their sitting rooms.