Philippa Langley has done it again. The self-described 61-year-old “housewife from Edinburgh” who led the discovery and exhumation of Richard III’s remains from a car park in Leicester in 2012 has now pulled off another extraordinary feat by claiming to crack what she calls “history’s greatest cold case”: the fate of the princes in the tower.

For decades, historians have debated what happened to Edward V, aged 12, and his nine-year-old brother, Richard, the Duke of York, after they vanished from the Tower of London in 1483. Most support the theory, immortalized by Shakespeare 100 years later, that the brothers were murdered on behalf of their uncle Richard, who had been made protector that year after the death of his brother Edward IV and was subsequently crowned king, with his nephews declared illegitimate.

Others accused of the murder include Henry Tudor, who would defeat Richard at the Battle of Bosworth Field in 1485 and be crowned Henry VII.

But now, after eight years leading a vast worldwide investigation dubbed the Missing Princes Project, Langley — who conceived the project on the day of Richard’s reburial, hoping to clear his name unequivocally — declared the puzzle once named “history’s greatest mystery” by readers of BBC History Magazine as categorically “solved.”

The brothers were not murdered, but separately removed from the Tower. Both then unsuccessfully fought Henry for the throne: Edward at the Battle of Stoke in 1487, where he was defeated but survived. Henry’s supporters discredited him as an impostor. Having taken the unknown boy from the battlefield, they gave him the invented name of Lambert Simnel, claiming he was the ten-year-old son of a tradesman. They pardoned him and gave him a job in the palace kitchens.

Prince Richard’s troops landed in England three times in 1495, 1496 and 1497, when he was captured. A confession was forced from him saying he was Perkin Warbeck, the son of a French boatman. He was hanged in 1499.

“One hundred percent these young men who led the battles were the princes. The stories about the princes being murdered and Perkin Warbeck and Lambert Simnel are so full of holes with no proper evidence to support it, but now we have all of this documentary evidence that the princes both lived,” says Langley, friendly but deadly serious in manner, from her Edinburgh living room which became the project’s headquarters.

The key pieces of evidence, expanded upon at length in Langley’s latest book The Princes In The Tower and a Channel 4 documentary, include a receipt found in Lille, France dated December 1487, recording King Maximilian of the Holy Roman Empire’s payment for 400 longpikes (weapons for elite troops) to Margaret of Burgundy, Edward IV and Richard III’s sister, who supported her nephews.

“The stories about the princes being murdered and Perkin Warbeck and Lambert Simnel are so full of holes with no proper evidence to support it.”

Four of the receipt’s details confirm the weapons were for Edward V, with details confirming he was then — aged 17 — alive, after the battle of Stoke. “The police always tell you, ‘Follow the money’ — go into the day-to-day administrative accounts, because these are not written for public consumption, and there’s no reason for them to lie,” Langley said.

Even more compelling is the evidence for Richard of York’s survival in the form of a witness statement uncovered in the Netherlands by Nathalie Nijman-Bliekendaal of Langley’s Dutch Research Group. Written in the first person, it records the Duke of York’s story from when he left sanctuary in Westminster in 1483, to his arrival at his aunt Margaret’s Burgundy court in 1493. The statement — like the receipt, subsequently fully authenticated by historians — provides extensive detail about his life in the tower and afterwards as he was moved around Europe.

“When I heard about it I had goosebumps. You absolutely don’t think you’re going find something like that,” Langley said. “We’d been trying to piece this jigsaw together bit by bit but once we’d had these documents authenticated suddenly everything went clunk, clunk, clunk into place.”

Philippa Langley with a facial reconstruction of Richard III.

With the help of dozens of experts, including police and crime scene investigation specialists, Langley ran her operation along the lines of a cold-case inquiry. More than 300 volunteers from around the world were encouraged to comb local archives, amassing more than 300,000 files of data and intelligence gathering, an amount so huge she had to have a special computer built to contain them all.

Langley resolved to launch the project even as Richard was being reburied, in response to an article calling him a “child killer.”

“We’d reburied Richard with dignity and honor. But we hadn’t really been able to lay him to rest because of the story of the princes,” she said. “I left Leicester with this new evidence-based research project formulating in my mind, right out of one and straight into another.”

How would she have felt if her investigation revealed Richard had killed his nephews? “I was 100 percent prepared for that. The police instilled in me I had to be completely open and not close anything down because I’d pre-judged it.”

As with the car park discovery, Langley’s feat is mind-boggling both in scope and outcome. Having grown up in Darlington, the daughter of an engineer father and office manager mother, she studied history only until O-level, and never Richard’s reign. “We did the corn laws and it killed history dead for me!” she said. She didn’t go to university, instead embarking on a marketing career.

“The police instilled in me I had to be completely open and not close anything down because I’d pre-judged it.”

She was 36, divorced and living in Edinburgh with two young sons when she was diagnosed with chronic fatigue syndrome after a bout of flu. “I was about to walk into a dream job with a leading advertising agency but I was ill, so that went. It was a really difficult time. But if I’d got the dream job, I wouldn’t have done what I did.”

Resting at home, Langley read a revisionist biography of Richard. She was riveted by the sympathetic portrayal of the man she’d previously understood to be a child killer. “All the records from Richard’s lifetime show overwhelming evidence he was loyal, brave, devout and just. Not to make him into a saint, he was a medieval man, but still a real progressive for the times he lived in. I thought, ‘Why don’t we know about the historical man? Why do we always roll out Shakespeare’s version?’”

Intending to write a film, Langley began investigating Richard’s life. The frequent traveling to places he’d lived exhausted her — “I’d have to bank sleep for days beforehand” — but she never disclosed her condition to the academics she encountered. “If you had chronic fatigue, people looked at you as though you were a shirker or there was something mentally unstable about you.” Did that give her extra empathy for how Richard was misunderstood? “There’s something in that.”

After being killed at Bosworth, Richard was buried in the Franciscan Greyfriars friary in nearby Leicester. Folklore had it his bones were dug up during Henry VIII’s dissolution of the monasteries and thrown into the River Soar. Langley never doubted this. “I hadn’t even thought about Richard’s death, it was his life I was interested in.” But in 2004, she visited the site of Greyfriars, the size of five international football pitches, now largely covered by council car parks.

“In the northern end of the social services car park [I] had this intuitive experience I was walking on his grave,” she said. The following year she revisited the car park. “I had exactly the same experience — freezing cold on a warm spring day, this time besides the hand-painted letter R — which of course stood for ‘Reserved’.”

Convinced that Richard was buried there, Langley began researching the bones-in-the-river story, discovering no evidence for it. She then persuaded the University of Leicester’s Archaeological Services to dig up the car park, despite their warning the chances of success were one in a million. She never mentioned her premonition to them.

“All the records from Richard’s lifetime show overwhelming evidence he was loyal, brave, devout and just.”

“Already people were ridiculing me,” she said. “Traditional historians were saying this is an unhinged woman, who’s emotional and should never have been involved in this project. If you’re a woman doing something like this, who’s not a professor, you lay yourself open to it.”

Of the university staff, she says, “I’m sure they probably thought they were being nice to me, but they were giving me the pat-pat-pat on the head and I just had to smile and ignore it because it was never going to be about my ego, it had to be about the job of getting the tarmac cut.” #MeToo changed her perspective. “If the dig happened now I don’t think that would happen, but if it did I would flag it and I would stop them.”

The lowest point came when an initial sonar scan indicated there was no church beneath the tarmac. Leicestershire Promotions, who’d provided funding, stopped it. “It looked like we were on a wild goose chase. I said, ‘This is crazy, I can’t do it anymore.’ It was my ex-husband who said, ‘Don’t give in now, it’s always darkest before the dawn.’”

Langley turned to members of the Richard III society to raise the necessary $16,500 for the dig to continue. Just hours after it began, a skeleton was found beneath the “R” that DNA tests and carbon dating confirmed as Richard’s. In 2015, millions of people worldwide watched his royal reburial in Leicester cathedral. Three years later, Langley was awarded an MBE.

The story was documented in last year’s film The Lost King, directed by Stephen Frears, to the annoyance of the university, who were portrayed as humoring Langley because they needed cash, then hogging the credit for the discovery. The academic Richard Taylor is reported to be suing for damages over his portrayal. “Allegedly suing,” Langley says gnomically. “Steve Coogan [who co-wrote and starred in the film as Langley’s ex-husband John] and [the screenwriter] Jeff Pope did their due diligence. They’ve looked at all of the contemporary source materials, a documentary crew was there the whole time.”

Seeing herself portrayed on screen by Sally Hawkins was “tough, because it relived that emotional roller coaster. It had been so exhausting doing all that with my illness and two young children. It was tough for my sons to see it too — they’re in their twenties now — but so often in their childhood I was physically present but mentally absent, or travelling to Leicester and London.”

She wavered about whether to allow Frears to include her car park “intuition”. “In the end, I thought, ‘No, it’s part of my story, it was the catalyst.’ I got hammered for it but I would do it again.”

No hunch drove the Missing Princes project — simply determination to separate truth from myth. Astonishingly, Langley learned that the case could have been solved in the 1950s when a Dutch historian was notified about Prince Richard’s account but — without even examining it — rejected it as a forgery.

“So many times historians pre-judge and come in with an opinion that closes off something that they should be investigating. Young historians get in touch with me in despair, saying, ‘We want to question, question, question because that’s the only way we’re going to make discoveries.’ But there’s a handful of leading institutions in this country where they’re patronized, threatened and bullied. One was told, ‘You won’t have a career here if you question, you have to find a new way of saying old things.’ After all, if you’ve made a career of following a certain line, you have to keep going, your own reputation matters more to you than Richard’s reputation.”

Langley will continue researching the princes’ eventual fate, but is meanwhile leading four other projects including the Hidden Abbey project in Reading to discover if Henry I is buried under — yes — a prison car park. “I should write a book, ’Car Parks Of The World by Philippa Langley’,” she says with a smile. She’s clear about the message from her triumphs. “Give something one more shot, you never know where it’s going to lead.”

Julia Llewellyn Smith is a journalist for The Times of London