In London's prime jewellery quarter of Hatton Garden, doing well in business depends heavily on who you know. Perhaps that is why so many Jewish traders - from the Charedi diamond merchants to secular shop owners - have managed to prosper. An old-school way of doing business persists. Buyers still barter, sellers settle through gentlemen's agreements and dealers know every retailer by face and name.
"We're in our own bubble - there's nowhere else like it," says diamond mounter Michael Lynton, one of the stars of Diamond Geezers and Gold Dealers, a prime-time, behind-the-scenes ITV documentary broadcast last night. Filmed over three months, the hour-long programme follows some well-known Hatton Garden characters - and relative newcomer Leigh Stutman - as well as shoppers looking for bespoke jewellery and jaw-dropping engagement rings. It also captures the "wheeler-dealer" lifestyle of traders haggling face-to-face. One of the many who commute to Hatton Garden from the north-west London and Hertfordshire suburbs, Lynton says the jewellery trade has traditionally appealed to Jews and estimates that more than 70 per cent of Hatton Garden traders are Jewish.
"Everyone knows everyone. We give our word on deals. You stick by your word. If you don't, you're not considered a gentleman. If we had a load of paperwork, there would be complete chaos."
Lynton, 66, is shown in the programme sculpting a bird with precious stones for a wealthy client. He works on his tiaras, brooches and bangles from a windowless basement with only a radio for company. He has sculpted precious stone-encrusted pieces worn by members of the royal family and exhibited in the Victoria & Albert Museum.
The Pinner Synagogue congregant was introduced to the trade by family members and served his apprenticeship at a top jewellery house after winning a competition run by the Jewish Board of Guardians in 1963.
He has seen the Hatton Garden clientele change dramatically over the decades. "Unfortunately, the aristocracy are not what they were," he reflects. "No, many of our clients are from the Far East or Dubai. They want some crazy tasteless things but we give them what they want." He declines to discuss what they pay.
Diamond Geezers captures a way of operating often far removed from the digitally savvy contemporary workplace. Lynton, for example, gets "lots of commissions" without the need for a mobile phone, computer, or even a business card. Many of his orders come from the local Jewish-owned Holts Group, which is shown briefly in the documentary. "People like speaking to me," he explains. "They like that human interaction."
It's a throwback world - and also a male dominated one. The only woman trader featured in Diamond Geezers is 25-year-old Stutman, a bubbly blonde known as the "sweep fairy". She stomps around in ankle boots and overalls, hoovering floors, wiping bins and cleaning sinks in the search for "gold dust".
She also dons rubber gloves to sift for gold through packs of teeth purchased from dentists, a task that takes some getting used to, she giggles. Stutman, who has worked for her uncle's company Presman Mastermelt for more than two years, travels across the country collecting thousands of pounds worth of gold that design studios and workshops perceive to be rubbish.
The work environment she inhabits is alien to most people of her age. She is one of the youngest people working in Hatton Garden and "the only girl on the road.
"Everything here has to be done face-to-face," she says. "There's that whole trust issue. People like to know who they're dealing with.
"In a couple of weeks, I'll be driving eight-and-a-half hours to Penzance to pick up gold dust. I'll drive, not have them send it to me. It's just not how the trade works. That's why I spend three nights a week out of London.
"It's a tough industry. People work hard for small margins. But I love what I do. It's rewarding to make something out of what people consider to be rubbish."
The Birmingham University media studies graduate says that, to help her network, she has started golf lessons. "I'm probably the worst golfer in the world, but you have to put yourself out there or end up in the background.
"People underestimate me but I don't mind that. I work hard and like to prove people wrong. But it would be nice if there were more young people."
She bristles when fears are expressed over Hatton Garden's future, yet concedes "it's changing. A lot of people are having to close their workshops because rent is going up, or they are given notice. Everyone is trying to stay as close as possible, because if someone needs a polisher, all they need is to run across the road. Their whole world revolves around Hatton Garden." Working in the industry has given Stutman a clearer idea of what she wants in an engagement ring. "I don't look at jewellery in the same way anymore. I want someone to make it, not just get it from a retail shop.
"There's a story behind a piece of jewellery. I don't know many other industries that are like it. I never thought I would go into it in a million years but I don't think I'll ever leave. I'll be here forever."
Orthodox father-of-four Jonny Marks is another featured in the programme. The antiques dealer is filmed doing deals in the back of a cab.
Speaking before transmission, Leigh Stutman and Michael Lynton confess to being a little nervous about their portrayal.
"I thought it would just be something on a local channel - not ITV," Lynton laughs. "Leigh and I are going to go and hide in a corner until this goes away."
But the grandfather-of-two admits to more pressing worries. "My grandchildren live in Netanya and get scared when the sirens go off. We're worried for them, for my two sons in Israel, for everyone. We just want it to end."
He hopes Diamond Geezers will inspire "more Jewish boys and girls to come into the trade. In Jewish society it's always about 'my son the doctor, my son the lawyer', but there are other things - a steady living. My pieces will live on forever."