Judi Dench has called for a disclaimer to be added to each episode of The Crown, saying the hit Netflix drama has begun to verge on "crude sensationalism".
The screen and stage veteran said despite previous statements by the streaming giant that the show is a "fictionalised drama", there was a risk that "a significant number of viewers" would take its events as historical truth.
She added that "wounding suggestions apparently contained in the new series" would prove "damaging" to the monarchy and could not go unchallenged.
Dench made the remarks in a letter to The Times, following previous concerns voiced by former British prime minister John Major, about the content of The Crown’s highly anticipated fifth series, which will launch on 9 November.
Major is said to have described the upcoming scenes, which reportedly depict the King, then the Prince of Wales, plotting to oust the Queen, as "malicious nonsense".
It is expected to show Charles cutting short a holiday with Diana, Princess of Wales, to host a secret meeting with Major at Highgrove in 1991.
"Sir John Major is not alone in his concerns that the latest series of The Crown will present an inaccurate and hurtful account of history (News, Oct 17)," Dench wrote.
"Indeed, the closer the drama comes to our present times, the more freely it seems willing to blur the lines between historical accuracy and crude sensationalism.
"While many will recognise The Crown for the brilliant but fictionalised account of events that it is, I fear that a significant number of viewers, particularly overseas, may take its version of history as being wholly true."
Dench said that the suggestions expected to be made in the new series were "cruelly unjust to the individuals and damaging to the institution they represent".
She continued: "No one is a greater believer in artistic freedom than I, but this cannot go unchallenged.
"Despite this week stating publicly that The Crown has always been a ‘fictionalised drama’, the programme makers have resisted all calls for them to carry a disclaimer at the start of each episode.
"The time has come for Netflix to reconsider - for the sake of a family and a nation so recently bereaved, as a mark of respect to a sovereign who served her people so dutifully for 70 years, and to preserve its reputation in the eyes of its British subscribers."
For the forthcoming series of the lavish royal drama, which features recast roles, Dominic West stars as Charles, while Elizabeth Debicki plays Diana and Imelda Staunton the Queen.
A spokeswoman for The Crown previously said: "The Crown has always been presented as a drama based on historical events.
"Series five is a fictional dramatisation, imagining what could have happened behind closed doors during a significant decade for the royal family – one that has already been scrutinised and well-documented by journalists, biographers and historians."
The programme's creator, Peter Morgan, also defended the forthcoming series in an interview with US publication Entertainment Weekly published this week.
"I think we must all accept that the 1990s was a difficult time for the royal family, and King Charles will almost certainly have some painful memories of that period," he said.
"But that doesn’t mean that, with the benefit of hindsight, history will be unkind to him, or the monarchy. The show certainly isn’t."
Netflix has also said the sixth and final series of The Crown will not depict the Paris car crash that killed Diana in August 1997, contrary to media reports.
It is understood that the series will show the lead-up to the fatal incident as well as its aftermath but not the crash itself.
The fourth series of the lavish Netflix drama also attracted criticism for allegedly not doing enough to ensure viewers knew it was a work of fiction.
Source: Press Association