Prince William’s former royal aide reveals his mother’s secret MI5 role

Jamie Lowther-Pinkerton grew up knowing his mother had led an “amazing life.” But there was one chapter she rarely spoke about.

After World War II, Sue Lowther-Pinkerton joined MI5 and worked in British intelligence during the Cold War. But she revealed little to her children about that part of her past.

Decades ago, while watching a documentary with her children, Sue let something slip.

KATE MIDDLETON SCALES UK’S THREE HIGHEST PEAKS IN 24 HOURS WITH A DEEPLY PERSONAL MESSAGE FOR CANCER SURVIVORS

“We were watching a documentary one afternoon about 30, 40 years ago,” Lowther-Pinkerton recalled to Fox News Digital. “And there was a thing called the ‘Cambridge spy ring,’ which were Soviet agents who had infiltrated the British system. And there was a great mystery about who the fifth man was. And up pops the documentary maker saying, ‘Well, it could be Sir Roger Hollis.’”

Hollis served as director general of MI5 from 1956 to 1965. He later became the subject of allegations that he had secretly worked for the Soviet Union, claims that were investigated but never proven.

Sue didn’t hesitate.

WATCH: PRINCE WILLIAM, HARRY’S FORMER ROYAL AIDE REVEALS MOTHER’S SECRET PAST

“My mother, without missing a knitting stitch, said, ‘Absolute nonsense. He was a total gentleman and a patriot.’”

“[My sister and I] both looked at her sideways as if she was completely mad,” Lowther-Pinkerton said. “I tried to get more out of her, but she was of that generation who quite rightly just didn’t want to talk about it.”

Lowther-Pinkerton said he was in his mid-20s before he and his older sister learned of their mother’s intelligence career.

MI5, formally known as the Security Service, is Britain’s domestic intelligence agency. According to MI5’s official history, the agency traces its origins to the Secret Service Bureau, established in 1909. The bureau was later divided into domestic and foreign sections that developed into MI5 and MI6.

That rare glimpse into his mother’s past stayed with Lowther-Pinkerton for decades. Now, her extraordinary life has helped inspire his novel, “Beyond the Edge of Light,” a wartime love story. Its central character, Missie, a rebellious young woman who joins military intelligence, was inspired by Sue, who died in 2023 at age 99.

Long before Sue entered the secretive world of MI5, she had already lived a life of adventure.

LIKE WHAT YOU’RE READING? CLICK HERE FOR MORE ENTERTAINMENT NEWS

As World War II unfolded, she worked on NAAFI (Navy, Army and Air Force Institutes) vans serving tea and food to troops and painted white lines on roads before she was old enough to enlist. In 1942, she joined the Auxiliary Territorial Service, the women’s branch of the British Army.

She was later posted to the Royal School of Artillery at Larkhill, where she drove gun limbers — vehicles used to transport artillery equipment — across firing ranges. Because the work was considered dangerous, she received an additional four pence a day.

After the war, her work took her into an even more secret world.

“She went into secret service,” Lowther-Pinkerton said. “So she joined MI5, which was the equivalent. It’s a sort of mixture between the FBI, I think, and the CIA. And she was in that during the Cold War.”

Sue’s intelligence career began even before she joined MI5. According to The Telegraph’s obituary, she worked in Army intelligence in Singapore after leaving the military in 1948. There, she was entrusted with secret communications concerning HMS Amethyst’s planned 1949 breakout from China’s Yangtze River.

After returning to Britain in 1951, Sue joined MI5 and worked at Leconfield House. But she remained fiercely guarded about what she did there — even with her son, who would go on to serve in the Irish Guards and the Special Air Service (SAS).

GET ENTERTAINMENT SCOOP DELIVERED RIGHT TO YOUR EMAIL BY CLICKING HERE

Growing up, Lowther-Pinkerton heard stories of his mother being raised in India and eventually getting “kicked out of every educational establishment she ever went to.” He described his mother, who didn’t see her parents for years on end, as “incredibly wild.”

Sue received 11 marriage proposals before Lowther-Pinkerton’s father, Anthony Hull Lowther-Pinkerton, or “Rumpty,” a “great big Anglo-Irishman” who was “everybody’s life and soul of the party,” wooed her.

“[They] had all of us children and went to live in Suffolk, which is where I grew up,” he said. “… [My father] could go up and down in moods. And my mother just … kept the family going absolutely on the straight and narrow through the middle with her calmness really. That was the great thing about her. Nothing fazed her.”

“I remember one occasion when my father got really down in the dumps,” he recalled. “She made really good roast potatoes for lunch. And she’d obviously had enough. She got this potato, and she flung it down the dining room table with [my sister] Sarah and me on either side thinking, ‘My goodness, what’s going to happen now?’

“And she hit my father clean between the eyes. My father was literally crying with laughter within about 20 seconds. She just knew. It wasn’t always roast potatoes, but she knew how to deal with him.”

According to Sue’s obituary, she remained in MI5 until leaving in 1956 to start a family. For almost 50 years, she helped organize the annual Poppy Appeal, a fundraising campaign supporting veterans, active-duty service members and their families. For several decades, she also delivered Meals on Wheels to remote cottages and farmsteads.

PUT YOUR ENTERTAINMENT KNOWLEDGE TO THE TEST AND SEE HOW YOU SCORE

Lowther-Pinkerton’s life also took an unexpected turn. He went on to serve in the royal household as an equerry to Queen Elizabeth the Queen Mother.

“She was an absolute joy to be with,” he said with a smile. “She was like everybody’s favorite granny. She had a bolt of steel running down her spine, so nothing fazed her.”

“She was the daughter of a Scottish girl who grew up in Glamis Castle. When she was 15, her favorite brother was killed in the trenches in the First World War. And Glamis Castle was given over, at least a part of it, to being a military hospital for wounded soldiers coming back from the First World War.”

“Like my mother, she had an incredibly sharp memory,” he continued. “I remember sitting with the Queen Mother at lunch and talking about the war. It was enlightening. And she had a wonderful sense of humor. I absolutely adored her.”

WATCH: FORMER ROYAL AIDE RECALLS LESSON HE LEARNED FROM PRINCE WILLIAM

The gig came with perks. Lowther-Pinkerton laughed when reminded that he would mix the martinis for her parties. He previously told People magazine the drinks were seven parts gin with “a whiff of vermouth.” According to the outlet, he would top her “decent-sized drink” with ice.

Lowther-Pinkerton served as a private secretary to Prince William, Prince Harry, and later Kate Middleton, from 2005 to 2013, People reported. He served as a mentor for the princes. His son Billy was a page at William and Kate’s wedding.

The couple later asked Lowther-Pinkerton to be a godfather to their eldest son, Prince George.

Lowther-Pinkerton said the remarkable women in his life have inevitably influenced his writing. “It all seeps in,” he said.

His mother, however, remains at its heart.

CLICK HERE TO DOWNLOAD THE FOX NEWS APP

“Somebody of strength, somebody who has their own opinions and is not going to be pushed around,” he said of the legacy he hopes Sue leaves with readers.