For Jeremy Turner, Cornwall was a childhood dream. The president of JetLease, one of the world’s few privately owned aircraft-leasing businesses, grew up in British boarding schools in the 1950s, when his family lived in what was then Malaya. Unable to get home, he spent the holidays at Machan, a boarding house for children near Helston, on the Lizard peninsula.

When Turner, 61, found himself casting about for a restoration project 10 years ago, Machan seemed like a great possibility – even though it was 5,000 miles away from his home and business in Houston, Texas, and Turner, born in Britain but now a US citizen, can spend only three months a year here without getting caught up in the UK tax net.

He is a multimillionaire, so money was no object. But could the great art moderne house of his childhood memories, overlooking Gillan Creek and Falmouth Bay, be bought? As luck would have it, the house was for sale – well, sort of.

“Actually, that’s a slight exaggeration,” Turner says. “But it had just been bought by somebody with the same idea as me – to renovate – and they realised it was a bigger project than they had thought. I got a real-estate agent to call them and they were happy to talk.”

After some negotiation, the owners agreed to sell – for less than £500,000, a reflection of the sorry state of the place. “The driveway was almost impassable without a 4WD, and the garden was completely overgrown,” Turner recalls. But it was still a place he remembered with fondness. “The two ladies who ran it were good to me when I was a child.

They put me in charge of feeding the four alsatians who guarded the house.”

The project became a family affair. “I had an ally in my former wife, Marianne, who lived in Exeter and has roots in this area,” he says. “We have been divorced for years, but it was useful to have somebody I trusted here, and somebody who knew my taste. It killed about 17 birds with one stone.”

Turner enjoyed giving his imagination free rein after a career spent with engines – when he left school, he began by “dabbling in motor racing”, then moved on to leasing commercial aircraft around the world, for “fairly staggering” sums.

At Machan, he took his inspiration from the house. A “machan” is a camouflaged hide for tiger-hunters, and Turner picked up this theme with enthusiasm: there are tigers burning brightly on the staircase, behind the lavatory in the guest bathroom, on the dinner service, on table napkins, even crouching over an elephant in the centre of the great circular dining table.

Every step of the way, Turner was there, tweaking, adding, improving. His daughter Helen, a textile designer, was responsible for the jungle stained-glass window on the stairs, and for the bathrooms, though her father chose the themes. One guest bathroom is in the style of the artist Henri Rousseau – “But Helen does better animals than Rousseau,” Turner says, “so I asked for his flowers and her animals.”

Marianne also made suggestions, which Turner embellished. She set about sourcing references from 1929, the year they believe the house was built. The date became an inspiration: the tiles around the swimming pool were copied from a railway poster of the same year.

Local craftsmen provided many of the fittings, according to Turner’s vision. Stained-glass windows and lights are from Cober Valley, Porthleven, and most of the furniture was made to order by Rozen Furniture, in Helston. The fireplace in the living room is a copy of one at Chelsea Cloisters, in London, rendered in white Spanish marble. Turner was responsible for the design of the furniture, including the extraordinary collection in his daughter’s room, which he describes as “Charles Rennie Mackintosh on acid” – a fair description of the elongated pieces in white and lilac.

It’s obvious Turner has had great fun, but it works. He is an enthusiastic tour guide, showing off the pool, the guest terraces, the wine cellar, the orangery, even a 1920s-style motor launch in the garage, next to a new Aston Martin Vanquish – “David Brown [the late owner of the company] was a friend, so I get preferential treatment.”

Turner is particularly pleased with the dining room, a circular addition with panoramic views that stands proud of the house, echoing its gentle curves. “The original dining room was totally rotten, but we didn’t have to get a demolition order – it fell over when somebody parked a JCB against it.”

He has no idea how much money he has spent during the five years of the project. “It was probably more than £2m, as we haven’t skimped on anything.”

Some of that money went on buying back land that once belonged to the property. It now stands in 13 acres that slope down to the beach, where Machan’s owner can rent a mooring on Gillan Creek.

Just three or four acres of the land have been tamed so far, and there are still five or six hidden on the opposite side of the valley. Buried beneath years of tangled undergrowth are old magnolias, windmill palms, gunneras, eucalyptus trees, Chinese dogwoods and a series of interconnecting ponds – the remains of some long-forgotten garden, waiting to be brought back to life. “Rumour has it that the Monterey pines so typical of Cornish gardens may have come first to Machan,” Turner observes.

The fourbed, four-bath main house, with granny flat, has been complete since 2003, but Turner is pulling out: Machan is on the market for £4m. The project has been a success – up to a point. His original plan was to retire there, but he’s not ready for that yet.

“In a way, this project has come too soon in my life,” he explains. “I should have left it for 10 years. It’s completely crazy, having a 10,000 sq ft house for three weeks a year.”

There’s also the wife to consider. In 2001, Turner was in Moscow to see the aircraft manufacturer Ilyushin. The deal foundered, but he met a blonde doctor in a hotel lobby. It was love at first sight, and within days they were engaged to be married, despite the fact that Svetlana, 25 years his junior, spoke no English and he spoke no Russian.

Lana – as Turner calls her, after the Hollywood star – has since completed a project of her own – a penthouse apartment for them both in Houston – so they are looking for something to take on together. It’s not easy, though. Turner would choose the south of France this time, but Lana, who has now learnt English, is loath to tackle another language. America is difficult, they say, for security reasons. Cornwall is beginning to look like a good idea.

Machan, in Gillan, Helston, Cornwall, is for sale for £4m with Hamptons; 01993 824546, www.hamptons.co.uk

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