Queen Elizabeth told UK army chief Prince William and Harry could fight on front line

General reveals she said: ‘My grandsons have taken my shilling, therefore they must do their duty’

Queen Elizabeth II. PA

A new documentary claims the late Queen Elizabeth authorised Prince William and Prince Harry to fight in Afghanistan, saying: “My grandsons have taken my shilling, therefore they must do their duty”.

It was decided Prince William, as a future king, would not serve on the front line, Gen Sir Mike Jackson said as he revealed Queen Elizabeth’s comments in an ITV series.

The Real Crown: Inside the House of Windsor is a five-part series that can been viewed in full from April 20.

Gen Jackson, who served as Chief of the General Staff from 2003 to 2006, says in the final episode: “The chiefs have an audience with the queen once or twice a year.

"You need to have done your homework. She’s very wise.

"I used to tell my staff, see if you can get the midday slot because after half an hour or 40 minutes the queen would ring a small bell and, 'Time for a sherry, I think, CGS.' 'Very good idea, ma’am.'

“What goes on in those audiences and who says what to whom remains for the two people involved.

“And I will break the rule … about not divulging what goes on on this one occasion when she was very clear, she said: ‘My grandsons have taken my shilling, therefore they must do their duty.'

“And that was that. But it was decided that for Prince William as heir to the heir, the risk is too great. But for his younger brother, the risk was acceptable.”

Queen Elizabeth II's funeral: extraordinary images from an extraordinary day - in pictures

King Charles III follows behind the coffin of Queen Elizabeth II, draped in the Royal Standard with the Imperial State Crown and the Sovereign's orb and sceptre on top, as it is carried out of Westminster Abbey after her state funeral. Reuters

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The coffin is carried into St George's Chapel for the Committal Service, in Windsor Castle. AP

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Prince George looks towards his father Prince William during the Committal Service at St George's Chapel. Getty Images

Queen Elizabeth's coffin is driven along the Long Walk towards Windsor Castle. Reuters

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King Charles and members of the royal family follow behind the coffin as it is carried into Westminster Abbey. PA

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Prince Harry was an army officer and Prince William an officer cadet when Gen Jackson was head of the army.

The younger brother served two tours in Afghanistan, where UK forces were part of a multi-national operation fighting the Taliban insurgency.

In Prince Harry’s first tour of Afghanistan, during 2007-2008, he was a forward controller co-ordinating air strikes on Taliban positions.

His tour of duty was abruptly ended when foreign websites broke a media blackout on reporting details of his service.

With a burning desire to return to the front line, Prince Harry retrained as a helicopter pilot and was sent back to the front, serving as an Apache co-pilot and gunner during 2012-2013.

Prince William was an RAF search-and-rescue helicopter pilot but was not sent into an active combat zone, unlike his uncle, the Duke of York.

At 22, Prince Andrew served in the Royal Navy as a Sea King helicopter pilot in the Falklands War in 1982.

His service included flying his aircraft as a decoy target, trying to divert deadly Exocet missiles away from British ships.