The monarchy is facing the "end game" and may not last longer than Prince William's reign, according to an author and critic.
Booker Prize winner Hilary Mantel said she thinks the Queen is in a lonely position and cannot abdicate, suggesting she might be the last person who believes in the monarchy.
Speaking to The Telegraph, Mantel said: "I think it’s the end game. I don’t know how much longer the institution will go on. I’m not sure if it will outlast William. So I think it will be their last big era.
"I wish the Queen had felt able to abdicate, because Charles has had to wait such a long time. I understand that she thinks of this as a sacred task, from which you simply cannot abdicate, whereas the rest of us think of it as a job, from which you should be able to retire."
Mantel, 68, said the Queen was in a "lonely position", suggesting: "I wonder if she’s the only person who really believes in the monarchy now, and I’m sure she believes with all her heart."
Author Mantel, who is best known for the Wolf Hall series, declined to comment on the situation around Prince Harry and Meghan, who were accused of dropping bombshells on the Royal Family during an explosive interview with Oprah Winfrey which aired in March.
She said: "I wouldn’t judge them. And I don’t believe we will ever know, really, what has happened there. So I just wish them well."
Mantel, who faced criticism in 2013 when comments she made about the Duchess of Cambridge emerged, said there was no longer legitimate public interest in the Royal Family.
Of the funeral of Prince Philip, she said: "No other family would be expected to parade a very elderly, newly widowed lady before the TV cameras, and yet it’s taken for granted that’s what will happen – just as it’s taken for granted that a new royal mother will appear beaming on the hospital steps within a day of giving birth.
"There’s no legitimate public interest behind it."
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In 2013, Mantel compared the Duchess of Cambridge to a "jointed doll on which certain rags are hung", which was taken as an attack on Kate.
However the writer's comments were intended to note an ongoing fascination with royal women's bodies, and to be sympathetic to the roles which Kate had to fulfil.
In one part of the speech, Mantel said: "We don’t cut off the heads of royal ladies these days, but we do sacrifice them, and we did memorably drive one to destruction a scant generation ago. History makes fools of us, makes puppets of us, often enough. But it doesn’t have to repeat itself."
She continued: "I’m not asking for pious humbug and smarmy reverence. I’m asking us to back off and not be brutes."
Despite the backlash, Mantel said she did not regret the speech, and said she ignored much of the social media critique.
Mantel received a Damehood in 2015, and was presented with the award by Prince Charles.
She is not the only person to question the future of the monarchy in the wake of the interview between Harry and Meghan and Winfrey.
Graham Smith, CEO of Republic, which campaigns for an elected head of state, previously said: "The unwillingness to criticise the Queen is not going to be inherited by King Charles.
"It's a very different, threadbare-looking monarchy when it’s King Charles and Prince William.
"I think the interview is extremely damaging, just on racism and mental health and I think it’s undone some of their good work."
He added: "It sets the scene for an incredibly difficult decade and one I am hopeful will mean it’s hard for Charles to be succeeded by another king."
However there has been ongoing support for the monarchy and the Queen - whose favourability ratings increased after the funeral of the Duke of Edinburgh.
Prince William also enjoys high levels of support, with one poll showing more people want him to be the next king than Charles.
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