I’M being driven at such speed I can hardly take in my surroundings. My driver brakes and accelerates as he expertly navigates hill and glen. From my limited vantage point, I spot yellowing leaves on the early autumn turn, overgrown beech hedges dripping in the drizzle, half-shorn sheep and newly turned fields whose raw dark soil echoes the overcast sky. As we rattle along, I feel compelled to commit to memory the route taken, just in case. But it’s no good: all I know is that I’m heading to somewhere top secret in deepest, glorious Perthshire.

Abruptly we turn into a majestic driveway and after a couple of hundred metres I’m given the signal to alight, pronto. I see an ancient high stone wall covered in ivy rise out of the tree-lined avenue. Just at that moment the sun bursts through the cloud and I’m greeted by a grinning Andrew Fairlie standing before a faded teal-painted wooden door that spells out Our Secret Garden. Trying not to giggle, he beckons me in.

Then, with a typically modest gesture from Scotland’s most celebrated chef, I’m granted the Big Reveal. I take off my metaphorical blindfold as Gregor Mathieson, Fairlie’s business partner and the “gatekeeper” of this intriguing project, lifts the latch, opens the door, and walks with me down a well-tended path, on both sides of which a veritable market garden of vegetables and fruits and herbs thrive, and past the restored original glasshouse of this beautiful 19th century walled garden.

It’s here that Fairlie has finally realised the dream he’s held since he opened his eponymous restaurant at the Gleneagles Hotel some miles up (or down) the road in 2001, regaining the Michelin star he’d originally attracted in 1996 and maintained for five years at Glasgow’s One Devonshire Gardens. Restaurant Andrew Fairlie has had two Michelin stars consistently since 2006 and remains unique in Scotland. Having the luxury of growing his own vegetables, fruit, herbs and flowers and cooking with them at the peak of freshness has, he has said, “changed his life” and galvanised his cooking and his du marche, degustation and a la carte menus beyond recognition. It has also been a source of solace as he continues his health battle with a partial brain tumour. He doesn't want to talk about that struggle today, apart from saying that he continues to live with it.

"The garden is a very calming influence and I am sure it has had a beneficial effect," the 52 year old, who started cooking at age 15 and is now one of 160 Grands Chefs du Monde, once told me. “It might be peaceful and quiet, but there's an energy in these plants that is so different from the crazy energy of the kitchen. Having this garden is the most exciting thing that's happened since the start of my career. It's given me a new direction and a whole new lease of life."

As I tread gingerly towards a shaded table in the middle of the garden I spot head gardener Jo Campbell – who came here from Raymond Blanc’s garden at le Manoir Aux Quat’Saisons in Oxfordshire – tending late summer heritage tomatoes, courgettes and a breathtaking variety of edible cresses in the glasshouse. I see trees heavy with heritage apples and pears and, beyond the border fence, a flock of dun-coloured Castlemilk Moorit sheep, a Scottish rare breed, and the pride of the private estate owner from whom Fairlie has leased the walled garden – on condition that it remain incognito to the general public.

But it’s what I see in the centre of this earthly Perthshire paradise that takes my breath away. Under the cooling shade of a large canvas awning is a wooden picnic table laid with a collection of ceramics and fabrics in 11 mesmeric patterned designs, inspired by this garden and its glasshouses, which were built by the Glasgow firm Mackenzie & Moncur in the late 1800s – and the all-male team of 12 gardeners devoted their lives to supplying the kitchen at the estate house with fresh produce and, later, fresh flowers for newly built Gleneagles Hotel before the garden fell into disuse for 40 years before Fairlie and his team took it over.

I experience the twin sensations of shock and delight. This is not what I was expecting.

When Fairlie first told me about this new project over the phone, I’d immediately conjured images of plates decorated with botanical drawings of flowers and plants in feminine greens and pinks. It sounded lovely, though I admit I’d struggled to imagine how it could be different from what has already been done.

But here I’m confronted by a mesmerising sequence of kaleidoscopic, Fibonacci-style patterns in various shapes and colours, all based on the patina and form of old tools, twines, taps and brackets from the ancient glasshouse and potting shed. Their incredible depth draws the eye to reveal more and more exquisite detail. Screen-printed onto fine-bone china charger plates, dinner plates, coupe dishes, teapots and cups and saucers, and digitally printed on to luxury linen and fine cotton velvets, they’re breathtakingly original and bang on-trend.

There’s Twine, a fascinating triangular close-up in monochrome colours; Harvest, a mesmeric pattern of mini heritage turnips with their leaves on in bright, almost acidic greens, reds and yellows; and Yield, inspired by marker tools to show where seeds were sown in the soil.

There's Fibonacci too, where the latch of the Secret Garden gate is represented in a repeat geometric pattern of teal and bronze, and Heirloom, a dizzying study of yellow, purple and orange heritage baby carrots complete with tops. Entangle is a wonderfully intriguing pattern of knots and twigs and plant fronds while Ripe is a deceptive repeat of rusty red bashed circles that could be mistaken for red pepper slices or even red chillies but which are inspired by the taps in the glasshouse. Lastly there is Nurture, Germinate and Glasshouse, a monochrome kaleidoscopic study in the sharp angles of the glasshouse roof.

Seeing my amazement, Mathieson takes a step back. Now the Glasgow-based designer Iona Crawford, who’s been waiting in the wings, stands up to take a bow. Her scarlet lipstick, black leather dress and spike heels add an urban edge to the scene that links her both to this new collection and to the world beyond these walls.

“It’s the grit, the harsh element in the tools of the garden that I liked, and their parallels with the tools that Andrew uses in his immaculate kitchen,” she says. “I like the masculine/feminine element, the play on perception, the feeling of getting lost and the element of surprise.”

The farmer’s daughter from Stirlingshire goes on to explain that when she was first shown the photographs of the garden, glasshouse and potting shed that had been commissioned by Fairlie and Mathieson from Alasdair Smith, she was “blown away” and immediately asked if she could do something with them.

The result is a new Scottish lifestyle brand, with every piece bearing the label Our Secret Garden by Andrew Fairlie and Iona Crawford. Vinyl wallpapers and fine art prints with handpainted frames by the former Glasgow restaurateur Ciaran Gourlay are also part of the growing collection, which is to be showcased at Decorex International Design Fair in London on later this month after a short exhibition at the Stallan Brand architecture studios in Glasgow from next Thursday.

Already, though, it has been snapped up by at least one high-end London retailer and a top interior design showroom in New York. The feedback has been extremely positive, with buyers saying they have seen nothing like it before – and enthusing about the uniquely Scottish storytelling that lies behind it. They say it’s very unexpected, and just what the market needs. The prices reflect the brand's high-end aspirations, with a 12in platter retailing at £120 and a 1sq m framed print at £700.

“I wanted to do what hadn’t been done before,” says Crawford. “In this garden there is tranquillity, peace and inspiration everywhere I look. The natural repetition really hit me and I was overwhelmed by how every natural thing is perfectly sequenced and the same every time. Coming here gave me a sense of losing myself, which was integral to the design process. It made me want to pay homage to the gardeners and the work they put in day after day in a way that conveys the wonder and mystery of what went on behind these walls.

“And the modern dining culture has morphed. Contemporary diners are seeking an aesthetic, sensory experience which I hope this collection delivers.”

Fairlie takes up the story. “It’s about letting people get access to the garden in a way they wouldn’t expect. And it’s fun, too," he says.

“With all the pictures of the garden that we’ve taken for the restaurant website, Instagram promotions or food guides, we were showing it off without opening it up to everybody. As someone who uses tools for a living, Alasdair’s photographs resonated with me as soon as I saw them and thought it would be a waste just to post them on our website. I thought, ‘We should do something with this,’ and went to see Iona at her atelier in Glasgow.

“Iona is a farmer’s daughter and she got exactly what we were doing. She can make the most basic utilitarian objects, like rusty old cogs and brackets, into beautiful psychedelic patterns. What she has come up with is way beyond what I thought we were going to get.”

It becomes clear that the collection was never intended for his own restaurant.

“We’ll get an idea of the general reception at Decorex. That said, it’s going to be a Marmite thing and some people won’t like it. But that’s good. If it had been a bland blancmange it wouldn’t have been us.”

Crawford adds: “Working with Andrew and Gregor on this has been a wonderful journey. Collaboration, especially multi-disciplinary collaboration, is absolutely key in design as well as in Andrew’s world. I found Gregor to be very switched-on aesthetically. We looked at shades of white for the mounts of the prints for 45 minutes.”

Collaboration, now also such a buzz phrase in food circles, has been important in Fairlie’s career from the start. He rarely speaks in the first person, always using "we" instead, and continually welcomes young chefs and front-of-house staff for training stages while retaining a loyal core team such as head chef Stevie McLaughlin and restaurant manager Dale Dewsbury, who have been with him since the beginning.

He met Aberdeen-born business partner Mathieson, whom Fairlie describes as “the gatekeeper for everything we do in the restaurant” some 25 years ago when both were working at One Devonshire Gardens. Mathieson, who studied hotel management at Napier University, left to help develop the boutique Malmaison chain with hotelier Ken McCulloch – who had also launched One Devonshire Gardens on to the world as a serious foodie destination – returning to work with Fairlie at Gleneagles when he asked him to help transform the space into what is now a secluded, windowless, oasis of calm and comfort studded with paintings by the Glasgow artist Archie Forrest. The pair also run the food and beverage consultancy Fairlie & Mathieson, which has worked with hotels such as Chewton Glen and Cliveden.

Asked what he thinks of the new collection, which he helped curate, Mathieson responds enigmatically: “This is a stimulating and fun new visual language which we can do other things with in the future. It will be used in unexpected ways, not on our uniforms or crockery in the restaurant. It has sparked our creativity.

“Our Secret Garden by Andrew Fairlie and Iona Crawford is beguiling. It relates to food yet it’s hypnotically kaleidoscopic, and based on very perfunctory, boring things we wouldn’t normally pay attention to. Iona has created something beautiful from something that nobody noticed for 125 years.”

Fairlie has never wanted to open a second restaurant, even though he is not contractually restricted from doing so. Neither has he aspired to television.

“We’ve always said ‘no’ to everything, including television,” he says. “And there’s always been the expectation that we’d do another restaurant, but to me that’s too predictable. I’ve always preferred to do something left-field and off the wall.

“People might wonder why a chef is getting involved in making wallpaper and plates. But we are very excited by this collaboration, which I see as an extension of the restaurant.”

The coup de theatre duly delivered, I reluctantly leave the garden. The latch falls as the gate closes behind me. We pile back into the car and drive off, and this time I don’t look where we’re going, for my mind is whirling at the thought of what the world is about to see.

Visit oursecretgarden.uk. Follow CrawfordXFairlie on Instagram