One of the props he’s most proud of is the original Death Star. The tale of how it ended up in his Seattle home is truly extraordinary. It begins in 1988 in Lake of the Ozarks, a quiet region of Missouri, three hours south east of Kansas City. Todd Franklin, a Star Wars fanatic and trainee cameraman at a local TV station, was filming for a story on antiques stores when he saw a strange object in the corner of a junk shop called Mexican Hillbilly. It seemed impossible, but it looked exactly like the Death Star. Franklin called Lucasfilm only to be told the Death Star had been blown up during filming. So much for that. Soon afterwards, a theatre bought the strange ball for display in their lobby.

Franklin went on to study film at college, where he attended a lecture by Marc Thorpe, a model maker from George Lucas’s special effects company, Industrial Light and Magic. Thorpe believed the prop was real. By then, the theatre had shut down, but he paid the building a visit anyway. “Everything had been sold - except the Death Star which was still sitting in the corner,” says Lopez. “They were using it as a trash can.” Franklin and two friends, he says, “picked it up for virtually nothing.”

Lopez declines to reveal how much he paid Franklin for it, or even guess how much it’s worth today, but says he knows the object’s real via a process called screen matching. “You take an image from the screen and find little artefacts that were unintentional - scratches, tears, details. The Death Star is easy because if you put a light source inside it, it illuminates with thousands of tiny light points. You can match the pattern to the onscreen image.”

Carrie Fisher and Anthony Daniels in A New Hope (1977) Alamy

Since the release of DVD and then Blu-Ray versions of the film, this technique has become easier for collectors. It was used by Stephen Lane to confirm another of his most impressive finds - Darth Vader’s Lightsaber from The Empire Strikes Back. “I was cruising the prop forums and this photo turned up from someone who’d seen it in a casino in America,” he says. Lane was sceptical. “There are a lot of replicas out there.” Nevertheless, he checked with his substantial store of reference materials, which include personal photos from crew members, for intricate characteristics. Everything matched, from the construction to the grip to the screws. “But the real fingerprints were two dings on the metal work,” he says. “It became undeniable at that point.”

He quickly encountered a barrier. “A casino is cash rich. How do you persuade one to sell something?” After a full year of efforts, Lane finally persuaded them. But at the last minute they mentioned a nearly impossible caveat. “They said, ‘I think we’re going to do this but one of our senior executives is a James Bond fan and we’d really like Daniel Craig’s tuxedo from Casino Royale.’ I was on the cusp of making this happen. It was so frustrating.”

He was once a sign writer, but Lane’s job now involves running the business he founded based on his passion. The Prop Store, launched in 1988, sometimes works with the National Film and Television School in Berkshire, helping them organise fundraising auctions. One day, the NFTS called Lane to ask his help with a sale of costumes.

“What have you got?” he asked.

“Eva Green’s dress from Casino Royale,” they said. “And Daniel Craig’s tuxedo.”

“You’re kidding,” said Lane. “I’m going to be bidding.”

Two months later, he’d successfully spent “north of £10,000” on the tuxedo. “I got in a black cab after the event and emailed the casino straight away saying, ‘It’s in my hand’. Within a week, the deal was done.”

Darth Vader in Empire Strikes Back Lucasfilm

But to the place where tatty props, frenzied collectors and hundreds of thousands of pounds meet are drawn the shady and the greedy. “There are a lot of stories about fake props that have sold for a lot of money,” says collector Jason DeBord, 41, of the Original Prop Blog. “There are people who study the films and figure out the different components so they can make a replica that’s pretty much indistinguishable. You can do it with $100 of parts from eBay.” Even items sold by crew members can be suspicious. “I’ve seen people who’ve worked on films turn around a little cottage industry selling things ‘from the film’ - but they seem like they have an endless supply.” An extremely senior Star Wars prop man, who worked on the original trilogy and is currently employed on the new film, even tried to sell me an anecdote about a prop. I politely declined.

There’s also “a grey market in things that shouldn’t have left the sets,” says DeBord. “The most interesting pieces are things people will never talk about publicly because they’re afraid Lucasfilm might come knocking. One of the best I’ve seen is a ‘hero’ (made for close-up) Lightsaber from the original trilogy.”

Collectors still fantasise about the whereabouts of pieces lost from the sets of the first film, A New Hope, and its immediate sequel, The Empire Strikes Back. One item on Stephen Lane’s fantasy list is a full Darth Vader costume. “There was only one made for A New Hope and that’s missing,” he says. “It went out to shopping malls and places like that to promote the film. Then the trail runs cold.” DeBord says, “I don’t know if it’s true, but one story I heard was that Lucas was sending a Darth Vader costume to a company that had a license to make replicas,” says DeBord. “Someone dressed up as a delivery man, rented a van and said ‘I’m here to pick up the costume for Lucasfilm’. It’s never been found again.”

Other mythical items include Luke Skywalker’s “macro binoculars” that he used on the planet Tatooine. “I handmade that from bits of camera parts,” says Roger Christian. “It’s worth $250,000, now, easily.” Also highly sought-after is a device called the “commlink”. “That’s the most legendary prop of all,” Christian says. “It’s a tiny transmitter that was held by Luke, the Stormtroopers and C3PO to communicate. I was up in the office when George called to say, ‘I need the commlink now.’ I unscrewed the bottom of this u-bend and out dropped a little filter. I put one little piece of rubber ring round it and rushed it to the floor. George put it straight into a Stormtrooper’s hand. It’s probably worth half a million dollars, there’s so much desire for this thing. It’s like the Holy Grail. It’s vanished for 30 years.” (I heard rumours that Star Wars producer Gary Kurtz has it in his extensive collection. Kurtz didn’t respond to a request for interview.)

And still, despite all these efforts, there are treasures as yet unburied. A few years ago, someone found a Stormtrooper blaster at a car boot sale in the UK. “If he hadn’t been a fan who’d researched it,” says DeBord, “he would’ve had no idea what it was and it would’ve been lost.” And that’s an ever-gathering fear for the super-collectors. “Many of the people involved in the original films are getting old,” says Lane. “If they pass away, someone might come along, empty the attic, have no idea what they’re looking at and throw it away. There’s a lot of stuff out there waiting to be found. It’s up to us to save it.”