Netflix has been urged to put a ‘health warning’ on The Crown to remind viewers that it is fiction after controversy arose over invented scenes.
Some, critics have said, have been treating the drama show as a "history lesson" and believe all the dialogue really happened.
Events which have been contested by Royal experts include the depiction of the affair between the Duchess of Cornwall and the Prince of Wales, which was shown on the series to have continued throughout his previous marriage.
One episode also shows Margaret Thatcher being humiliated and bullied by the Royal Family at Balmoral, which was an invented scene.
Royal insiders have joined a campaign launched by the Mail on Sunday which is asking the streaming service to add a disclaimer to the show.
Lady Glenconner, the former lady-in-waiting of Princess Margaret, said the portrayal of the late Royal was "unfair". The sister of the Queen is shown being rude to the Prime Minister and Princess Diana.
Earl Spencer, the late Princess Diana’s brother, told Love Your Weekend with Alan Titchmarsh yesterday that he agreed with the calls to mark the show as fiction.
He said: "The Crown asked if they could film at Althorp and I said obviously not. The worry for me is that people see a programme like that and they forget that it is fiction.
“They assume, especially foreigners, I find Americans tell me they have watched The Crown as if they have taken a history lesson. Well, they haven’t.”
"There is a lot of conjecture and a lot of invention, isn’t there? You can hang it on fact but the bits in between are not fact.”
Julian Fellowes told the Mail on Sunday: "I don’t really understand why not because in many programmes based on truthful events there is a disclaimer at the beginning that says some events have been conflated and some characters have been invented for dramatic purposes. That’s very common – you see it at the front of many, many programmes."
Ingrid Seward, the editor-in-chief of Majesty magazine, said that the scene where the Queen allows Mrs Thatcher to be humiliated on a deer stalking mission, on which she wore a bright blue coat with matching handbag and scarf was unfair.
He said: "The Queen does not like humiliating people. It simply in a million years couldn’t be further from the truth."
Peter Morgan, the creator of the show, has insisted that blending fact and fiction is essential for the drama show, but that the truth is never forgotten.
He said Peter: “We do our very, very best to get it right, but sometimes I have to conflate [incidents] . . . You sometimes have to forsake accuracy, but you must never forsake truth."
Mr Morgan has admitted that some scenes were dreamed up by show writers, including the one where Lord Mountbatten writes to Prince Charles of his "disappointment" in the young Royal, and beseeches him to marry Diana Spencer.
He said: "I made up in my head — whether it’s right or wrong — what we know is that Mountbatten was really responsible for taking Charles to one side at precisely this point and saying, ‘Look, you know, enough already with playing the field. It’s time you got married and it’s time you provided an heir.’"