The £2m question: is this painting a real Constable or a fake?

But despite his best efforts, the dealer failed, not once, but twice, to convince the experts and he was grudgingly obliged to sell it on, for a fraction of the £2 million it would be worth today if authenticated as an original Constable. It’s a decision he’s regretted ever since.

Seventeen years later, he’s returning to the case. For him this is “unfinished business”. So begins the first edition of Fake or Fortune?, which returns to BBC1 on Sunday for its sixth series.

“The stakes have never been higher,” says art dealer Philip Mould, who presents the programme with Fiona Bruce. And he, of all people, should know. He was that up-and-coming dealer of the 90s. The reputation at stake here is his and the quest a deeply personal one. Mould is at the centre of his own plot with a heavily vested interest in the outcome.

“When you’re revealing what you feel about a painting, you are pinning your reputation to it. I’d been turned down already, twice, and here I am trying to prove it for a third time in front of five million people in this country and in 40 to 60 countries across the world.

“As an art dealer, particularly as one gets older, reputational risk is as great as financial risk. To put it crudely, I didn’t want to look like a plonker! I couldn’t bear for people to think, ‘Oh God, is he still having a go.’ I thought long and hard about this. To fail for a third time would be very depressing indeed.”

Does he recall now how he felt when he first laid eyes on the painting, a breathtaking depiction of Willie Lott’s Cottage on the banks of the River Stour on the Suffolk/Essex border? For a moment he disappears into a dreamy recollection of a childhood obsession with Constable. “He’s an artist after my own heart… no one could use paint so fluently or impart the fugitive beauty of the English landscape in such a way.”

I bring him back to the question. “Ah yes, but you see, that’s it. I remember thinking this is the guy I know. This is the guy who could do it better than anyone else. It looked and felt like him. Believe me, nothing brings oxygen to the brain better than financial risk, but this didn’t look like stranger danger. I really rated it. I thought, ‘I am going to prove this damn thing.’’’

But proof that it was a Constable proved elusive. Constable was one of the most forged artists of the 19th century – many tried to emulate his work, and the experts found elements of this picture unconvincing. It also had little in the way of traceable provenance. When we first see the painting, it is adorning the wall of the home of Henry Reed, the client to whom Philip sold it in 2000 for £35,000.

“I said, ‘Henry, I’m going to sell you this picture but one day, one day I think we will be able to prove this is a work by Constable. I can’t prove it now, I don’t have access to the necessary provenance or expert endorsement, but you’ll have to trust me on this. I feel it in my waters. One day we will prove it.”

There is, of course, much more than Mould’s reputation at stake here. “Not only would this be the biggest financial uplift that we would have achieved on the programme, turning £35,000 into more than £2 million, but we are dealing with one of the greatest ever icons of English art,” he says.

“How many opportunities does a dealer have to add something substantial to a work so embedded in our cultural consciousness, our heritage?”

One wonders why, after all this time, Mould is willing to put himself through the wringer again – and so publicly. There’s still a very real risk his Constable could be a fake.

“I’m prepared to fail, but I couldn’t let go of the fact that there was what felt like a historical injustice that needed to be addressed. It felt unconsummated. That nagging itch had returned so strongly I could not ignore it any more.

“Crucially, though, the whole art world has moved on hugely in the past 20 years. We now know so much more about Constable’s techniques, the way he put his paintings together and we have digital access in a way we never had before. I see this as a cold case that needs reopening. A final push. My right of appeal.”

Everything in the way he describes this “case” conjures up the elements of a crime drama. The analogy is inescapable. I wonder how he sees himself – Morse perhaps? DI Alec Hardy? “Oh no, I’m just an art dealer,” he says with a certain knowing false modesty. It’s quite clear he relishes the parallels. Who wouldn’t?

“What is so exciting is the concept of jeopardy. You have the real potential to change someone’s life so you really engage with it. I like to think of the technical reports we do when we look deep into the picture and examine the body of the paint under the microscope as analogous to the pathologist’s report in a murder. The provenance and stylistic analysis are rather like creating a profile of the notional perpetrator.”

His excitement is palpable. So did he feel the odds were with them this time round? “I knew there was a high chance technically we would be able to find more evidence than we have historically. Thanks to the great work that’s been done by art historians, we now have factual data that can support the process of attribution. We can access hard facts: the materials used and the way brush strokes are applied. The science has come on a lot.”

These “forensics”, as he calls them, form an important part of the painstaking process they go through trying to solve the mystery. There’s ultraviolet, infrared and X-ray technology, as well as scrutiny under the microscope. It’s all rather nail-biting stuff.

“Midway through the process there was an unexpected and rather shocking revelation about pigments in the picture that didn’t seem in keeping with Constable. Of course it is logical,” he says. “There were doubts before. Why should modern experts not come up with the same results? But at that point I thought, ‘Oh God, here we go again.’”

We are also taken on a fascinating journey into the painting’s history. The search leads us across the globe from Constable country to the mansions of Beverly Hills, and from London’s auction houses to the banks of the River Tay in the Scottish Highlands as we discover a host of eccentric former owners, from “Whisky Tom” to scandal-ravaged oil tycoons in Los Angeles.

“Fiona’s activities in LA make a marvellous parallel narrative. I like to think of it as the equivalent of an airstrike. I was there rolling up my sleeves getting down and dirty in the paint and she was off in the sunlight of LA using her tremendous journalistic skills to home in on previous owners. It was a great pincer move.

“People often ask me what it’s like working with Fiona.” I hadn’t in fact asked, but of course I’m dying to know. They have a very engaging and playful on-screen chemistry. “I have learnt so much from her. Her skills in interviewing people. The way she likes to test facts in a forensic way. Of course we do that in the art world, but we can sometimes have our heads in the clouds as dealers. I mean, what is art? It’s an illusion in a language other than words, so it’s good to have someone to anchor you by focusing on the provable facts that a jury would understand.”

Speaking of juries, how did he feel on judgement day, when Constable experts Sarah Cove and Anne Lyles came to deliver a verdict? “Both buoyant and nervous. I felt we had done an exam to the best of our ability, answered the questions as well as we could and, if we were to fail, it wouldn’t be for the want of throwing everything we could possibly get hold of at it.

“But you can absolutely never be sure which way it’s going to go. There are examples in the past where I feel we have conclusively proved a picture and for their own reasons – reasons I cannot understand – experts have simply said no.

“That’s the beauty of it, the jeopardy. There is no other way of doing it. It’s just like a jury.”

So, if it is deemed to be the real deal, a Constable worth millions of pounds, will he feel a niggle of frustration at not having been proved right all those years ago? After all, the money could have been his.

“No, gosh no, definitely not frustrated. You can grow old and bitter as an art dealer. For me it will be the hugest sense of relief. The lovely thought that I was not deluded as a young man, and a sense of vindication. Above all, a sense of soulful delight and thrill at the knowledge that I will have added something to the portrayal of one of the most beautiful natural scenes in the canon of British art.”

So, fake or fortune? The jury is about to return its verdict.

By Hannah MacInnes

Fake or Fortune? is on Sunday 7.05pm BBC1