Getting to Know Derek Pratt, the Watchmaker's Watchmaker | Ref. 09
Mary Pratt on her father, meeting George Daniels, and Reuleaux triangles.
The late watchmaker Derek Pratt didn’t even have a Wikipedia page in January 2025. His daughter, Mary Pratt, wanted to change that.
Pratt (1938–2009) was a British watchmaker, known in collecting circles for his work with Urban Jürgensen in the 1980s and 90s, his friendship with George Daniels, The Oval, or the reconstruction of Harrison’s H4 chronometer. He was one of the finest watchmakers of his generation, completely committed to the craft of watch and clockmaking.
Mary Pratt grew up surrounded by her father’s work. Like any kid, she says she didn’t fully understand the magnitude of his work at the time, even if the watches and clocks in their home always seemed interesting.
Nowadays, she runs a production company in New York. But a few years ago, she began to discover and document her father’s work in earnest. Now, there’s a Wikipedia page for Derek Pratt. But for the more personal stories, Mary started a newsletter, The Watchmaker's Daughter—covering his love of bicycles, weather vanes, or their shared affection for Swatch.
Pratt was a historian of the craft—fluent in the techniques of Breguet, Harrison, or Tompion—and intent on carrying forward the tradition. Horology is overly or at least improperly used today, but Pratt was a true horologist, dedicated to the measurement of time, and the design, construction, and preservation of timekeepers.
Pratt has become especially known for his work with Urban Jürgensen, where he was technical director from 1982–2005. He became particularly well-regarded for the guilloché dials he made, crafted with antique engine-turning machines.
When his workshop was cleared out after he died, drawers full of discarded dials were found. While they appeared perfect, close-up inspection revealed the smallest of errors that had caused Pratt to reject them.
But his dial work was just the surface.
“On the hour, the whole house would ring. My dad did a fair amount of clock repair. His first workshop was a room in our apartment, and the whole house was filled with clocks he was working on or monitoring for accuracy.”–Mary Pratt
The Oval pocket watch for Urban Jürgensen was Pratt’s masterpiece, which sold for $4.2m in 2024. He began work on the pocket watch in 1982, endeavoring to complete it all—case, dial, movement—by hand. The Oval movement features a tourbillon, detent escapement with remontoir (incorporated into the tourbillon cage, a first), thermometer, and moonphase. It wasn’t ultimately finished until 2005 by Kari Voutilainen.
Perhaps because of his mechanical inclination, Pratt also appreciated other quirky inventions: his Wankel-engine Mazda, Dursley Pedersen bicycles, or water clocks.
I recently caught up with Mary to talk about her father, his watchmaking, and what it’s like growing up when your dad has a standing Sunday morning phone call with George Daniels.
Excerpts from our conversation below.
The Ref is a weekly story about a sometimes-forgotten watch or moment in history. Previous editions:
On clocks in the house
“I never had any aspirations to become a watchmaker, but exposure to watches, craftsmanship, and antiques definitely shaped me and my interests. I was surrounded by clocks and watches growing up.
On the hour, the whole house would ring. When I was young, my dad did a fair amount of clock repair. His first workshop was a room in our apartment, and the whole house was filled with clocks he was working on or monitoring for accuracy.
It was a great education for my eye from a very young age. It gave me a curiosity about all kinds of beautiful objects, not just watches and clocks.”
On Derek’s friendship with George Daniels
“[Pratt and Daniels] had their Sunday morning phone calls, which were famous in the horology world. They spoke every Sunday morning for years. To me, these are just childhood memories. They’d send each other faxes of sketches. George could come across a bit gruff on the phone. Once he called, we’d see my dad two hours later, if we were lucky.
I remember meeting George Daniels, and he was rather intimidating. Gravelly voice, very serious, always dressed in the best tweed, everything tailored.
My dad had a nice, calm voice, a pleasant demeanor talking to George. They probably talked about horology 99% of the time, and the rest of it was cars, motorcycles, and bikes. He was in his element, and genuinely loved talking shop.
On the day I was sworn into the Worshipful Company of Clockmakers, [clockmaker] Andrew King told me a story about how he and Daniels were visiting Derek. Derek spotted my sister and me across the footbridge, and went to say hello to us. Daniels was not too pleased about this—probably thinking something like who’s more important than I am.”
Daniels valued his friendship and partnership with Pratt. When Pratt died, he contributed to the remembrance in the British Horological Institute Journal, writing:
“Derek’s understanding of escapements was of great assistance to me. He immediately saw the benefit of the coaxial escapement and enthusiastically accompanied me in visiting factories to discuss its worth. We would take to the road early in the morning with coffee (and some brandy to relieve the cold), and spend the day discussing escapements with largely uncomprehending R&D departments.”
—George Daniels on Derek Pratt, after his death in 2009
On Derek’s work with Urban Jürgensen
In the 1980s and 90s, he was very actively engaged with Urban Jürgensen as technical director. These were some of his most productive years and innovative years. He hand-built movements with hundreds of components. It’s where he developed his remontoir that used a Reuleaux triangle, a shape he’d long been fascinated by.
On other clocks she remembers
There was this medieval clockmaker, Liechti, that made simple, ornamental iron clocks with floral embellishments. He was quite fond of them, charmed by them. I remember these distinctly as a child!
On her relationship with her dad’s work
The fact that he was so respected by his peers—as a child I just knew him as my dad. As I grew older, it’s been amazing to realize the level of respect he was shown and continues to have in the arena of independent watchmakers, the incredible refinement in his craft. He always strived for absolute perfection and went to great lengths to get there.
His guilloché work stands out. It cost him a lot of time and energy, but it’s something he really valued. The level of perfection—and the number of pieces he rejected—is just staggering.
Find Mary at The Watchmaker’s Daughter.
Further reading:
Derek Pratt: The Forgotten Watchmaker, A Collected Man
Inside Derek Pratt’s Oval Pocket Watch, Phillips
Remembering Derek Pratt, British Horological Institute
Derek Pratt, The Complete Horologist, British Horological Institute
Derek Pratt, Wikipedia
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