Prince Harry's decision to reveal the layouts of palaces in 'Spare' may prove 'dangerous' for the royal family: report

• A former head of protection for the royals criticized Prince Harry for details revealed in "Spare."
• In his memoir, Harry describes several rooms in royal residences, including Balmoral in Scotland.

The former head of protection for the royal family has spoken out about Prince Harry's decision to include details of royal residences in his new memoir.

Dai Davies criticized the Duke of Sussex's decision in an interview with The Telegraph, saying that "only a fool would reveal this kind of detail about the royals' inner sanctums."

"There is a reason Buckingham Palace never discusses any detail about its security operations, big or small," he told the newspaper. "It would never expect someone with such an intimate knowledge of private royal residences to disclose such information."

Throughout "Spare," Harry shares several behind-the-scenes details about what it was like to grow up in royal homes. For example, he discusses wine cellars at Highgrove House, the home of King Charles where he and William spent their most of their childhoods, where Camilla, the Queen Consort, would keep expensive bottles of wine and "absurd gifts from foreign governments and potentates."

Elsewhere he details the layout of Balmoral Castle, one of the late Queen's favorite residences, Clarence House, and how to find a room in Highgrove House nicknamed "Club H" where he and William would hang out as teenagers.

Davies called the revelations "problematic" and potentially compromising for the royal family's security operations.

"There have always been people who have tried to access parts of royal palaces," he said. "Whether they are fixated individuals with mental health problems or terrorists, this information could prove very useful."

The former protection officer also voiced concern over the details Harry revealed about how his security detail operated. While describing his first years at Eton, Harry wrote that he carried an electronic tracker and panic alarm with him at all times.

Royal residences have been broken into

Break-ins to royal residences have occurred, with a 22-year-old man gaining access to Buckingham Palace in 2019, according to Metro UK.

The best-known incident of royal trespassing occurred in 1982 when the palace faced one of its biggest security breaches in modern history.

Michael Fagan, an unemployed house painter, broke into the royal residence and entered the Queen's bedroom, where he is said to have exchanged a few words with Her Majesty before security arrived.

Fagan was committed to a psychiatric hospital after the incident, and "was in and out of jail on drug and other charges" in the years after, The Washington Post reported.

After the incident was portrayed in season four of "The Crown," Fagan discussed what he said actually happened in an interview with The Sun.

"She was wide awake when I got in there," Fagan said, referencing the Queen. "She sat up in bed and said, 'What are you doing here?' and then went off to fetch someone."

He also denied asking the Queen for a cigarette, which was shown in the drama, as that would've been "cheeky and disrespectful and something I just wouldn't do."

Buckingham Palace and representatives for Prince Harry did not immediately respond to Insider's requests for comment.