Prince Philip snuck a beer on his final night while hiding 8-year cancer secret, historian claims

Prince Philip battled pancreatic cancer for the last eight years of his life, a new book claims.

The Duke of Edinburgh was diagnosed with inoperable pancreatic cancer in 2013, royal historian Hugo Vickers wrote in "Queen Elizabeth II: A Personal History."

Philip died on April 9, 2021, at the age of 99.

"On the last night of his life, he gave his nurses the slip, shuffled along the corridor on his Zimmer frame, helped himself to a beer and drank it in the Oak Room," Vickers wrote of Philip's final moments, according to the Daily Mail.

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"The following morning, he got up, had a bath, said he did not feel well, and quietly slipped away," he added. "By this point, he had lived with pancreatic cancer for nearly eight years — far longer than the usual survival time from diagnosis."

Fox News Digital reached out to Buckingham Palace for comment.

Buckingham Palace previously said Prince Philip had died from "old age," just two months before his 100th birthday.

"The Queen was not there when he died," Vickers revealed. "There had often been times in earlier days when she had asked the staff to let her know when Philip was leaving, only to be told, ‘His Royal Highness left 20 minutes ago.’"

According to the historian, Queen Elizabeth "was ‘absolutely furious that, as so often in life, [Philip] left without saying goodbye.’"

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Philip had retired from public duties in 2017. At that point, he had allegedly been living with pancreatic cancer for roughly four years.

Philip had undergone an abdominal operation on June 7, 2013, during which doctors discovered his pancreatic cancer. The prince was 92 years old at the time.

"Doctors had detected a shadow on his pancreas, and had cut him right across his stomach," Vickers wrote. "The verdict was inoperable pancreatic cancer.

"He convalesced for two months at Windsor Castle, having good days and bad days, sometimes just sitting in the sunshine," he added. "There was a view that he might not be seen in public again."

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Prince Philip was seen in public for another four years until he retired from public duties on August 2, 2017, after completing more than 22,000 engagements.

"It was a wet day. Wearing a raincoat and bowler hat, he strode through the parade without a stick and chatted to the young men and the veterans," Vickers wrote. "When the parade gave him three cheers, he responded with a valedictory wave of his hat."

"After that final engagement, the Queen let the Duke do exactly as he pleased," he added. "He was at his happiest at Wood Farm on the Sandringham estate, and that became his home for the next two and a half years."

Philip kept a low profile in the years after his retirement.

"He enjoyed his carriage-driving, read voraciously and painted a little," Vickers claimed. "From time to time, the Queen went up by train to Norfolk to stay the weekend."

"Once again, she gave him a loose rein."