An Ex-Forger Created A $100 Million Fake Declaration of Independence For Jeffrey Archer's New Book

Jeffrey Archer asked artist Billy Mumford to create a copy of Jefferson's Fair Copy of the Declaration of Independence

The extraordinary real-life story of a friendship between a reformed ex-art forger and the police officer who arrested him has emerged in Jeffrey Archer's latest crime novel An Eye For An Eye, out Sept. 24.

Archer, who was on the hunt for realistic background for his book, called upon longtime collaborator and former Scotland Yard detective Michelle Roycroft to advise him about the fake art world.

She knew just the man – Billy Mumford, who was jailed in 2012 for two years after creating hundreds of paintings and passing them off as by famous artists. Roycoft, who was a senior member of Scotland Yard's Arts and Antiquities unit, first encountered Mumford when she tracked and arrested him in 2009.

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Remarkably, she and her fellow officers found him happy to fess up to his crimes. “I had been awaiting a knock on the door for 40 years. It was a bit overdue. I was always in the shadows. Then I stepped out into the light and Michelle was there!” Mumford tells PEOPLE. “Unfortunately,” he laughs. “Though not for Michelle and justice, of course.”

“During the arrest and searches and so on, Michelle was immensely kind to me and treated me with more respect than I deserved," he continues. "She did a very special thing for my wife — a great act of kindness and that enabled us to retain our dignity in trying circumstances.”

Roycroft, reunited with the reformed Mumford in Archer’s London penthouse on a recent afternoon, tells PEOPLE, “He knew the game was up and it was just a matter of time. The stress of waiting was almost worse than the actual event. Right from the word go he was helpful, he was affable, he was charming.”

“He is the only person I have put in prison who wrote to me," she adds. "He said ‘thank you for the way you treated me throughout the investigation.’”

Archer not only included Mumford, 75, in the book but he tasked him with creating two key pieces of art. One is an imagined drawing of a Rembrandt piece, Jacob Wrestling with the Angel, and the other a version of Jefferson’s Fair Copy of the Declaration of Independence. “My readers have to believe it is possible,” Archer explains as the reasoning behind the creations. (And it has echoes in last year's craftsman-created copy of the Imperial State Crown, for his last novel).

Both feature in An Eye for an Eye, the latest installment of novels featuring William Warwick and his nemesis Miles Faulkner. At the center of the plot is the possible existence of one of the rare versions of Jefferson’s Fair Copy of the Declaration of Independence, which could be worth tens of millions of dollars. The rare copies were sent by Jefferson to allies and carry two key lines which not only condemn slavery, but also lay blame for it at the door of King George III.

While that was not the version of the Declaration that was adopted in 1776, historians believe Jefferson wrote several others and sent them to contacts and friends. “We think there is [still] one out there and it would be worth $100 million,” says Archer, whose books have sold 275 million copies worldwide. “But it has probably been destroyed.”

If Jefferson’s alternative had been ratified, U.S. history would have been very different, the author adds.

“Jefferson was very outspoken,” Archer says. “One cannot forget the words of Kennedy, when dining with eight Nobel Prize winners in the White House saying this is the greatest gathering of intellects since Jefferson dined alone.”

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Standing with his creations in Archer’s apartment, Mumford — whose name is used in the book for Archer's forger — explains how he made the paper look genuine. He aged the paper “by using horse chestnuts. You boil them up in distilled water. It’s a bit of alchemy, really — and involved a lot of telling-off from the wife because the kettle tasted funny afterwards,” he tells PEOPLE with a smile. “To my satisfaction, it is Jefferson’s hand.”

The "Rembrandt," an imagined study or sketch of one of his paintings, is also in the book. “There is no history of any drawing to do with that painting," Mumford adds, of the process. "It drove me mad for three months.”

“It is easier to do a painting from a drawing but to do a drawing from a painting is immensely difficult," he explains. "Paint is quite forgiving; you can wipe it off, put your thumb in it and redo it. But mediums like ink and charcoal — especially on that scale — you have to get it exactly right.”

And he had a hard taskmaster. “When I looked at it, I was overwhelmed. If it had been bad I would have seen it was nothing like an Rembrandt,” Archer says.

Today, his expert eye is back at the writing desk, as he's working on the final installment of the Warwick series. And Roycroft will be helping advise him on that, too.

Mumford's life has changed since he got out of prison, and he has his own studio today selling legitimate versions of famous art. He recalls the day when Roycroft got back in touch to ask him about Archer's novel. “I said ‘Oh hi Michelle,’ like we had spoken yesterday. I said 'Last time I spoke to you I got two years.’ So I was a bit reluctant."

She told him she hoped there were no hard feelings. "I remember saying ‘You’re the good guys and your job is to catch the bad guys," he recalls. "She said, ‘And you were never a bad guy.’”

An Eye for An Eye by Jeffrey Archer comes out Sept. 24 and is now available for preorder, wherever books are sold.

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