The forecast for the Hebrides is variable, to say the least. But for the inhabitants of the island of Tiree it is getting brighter, thanks to a sleek modernist ferry shelter
"A cathedral is architecture, whereas a bus shelter is merely a building," Sir Nikolaus Pevsner famously proclaimed. As if to prove Britain's all-time greatest architectural historian wrong, a group of six Scottish sculptors and architects – along with a schoolmaster – in the remote Hebridean island of Tiree have developed a basic ferry shelter that is as highly distilled a work of architecture as you could hope for.

Not that there is anything flamboyantly in-your-face about the design – there are none of the CAD-induced swirls favoured and popularised by Frank Gehry and Zaha Hadid. Just the opposite: the shelter is a subtle and minimalist piece of architectural sculpture. And this is precisely what makes it so appropriate to its setting. In the galaxy of Scottish islands, Tiree is unusually flat, and what delights it does offer are similarly subtle.

The shelter is little more than a tunnel-like box structure with totally flat sides and roof. Its clean-lined, artificial form only accentuates the gently undulating pastureland and enormous ragged-cloud sky through which it cuts.

The tunnel starts as two parallel white walls that slice through a low grassy mound. It then switches suddenly into an enclosed timber structure lined in black bitumen felt that straddles an outcrop of natural bedrock. The tunnel culminates in a glass box set in a galvanized steel frame that crashes through a dry-stone field wall.

Inside the tunnel, an equally bold connection with the surrounding landscape is formed. As you enter the tunnel, the glass box ahead of frames a microcosm of Tiree landscape – a patch of pastureland, a white sandy beach, a bay, a low hill on the far side and a solitary cottage. And as you reach the box, the landscape opens up for you as if you are seeing it for the first time. The shelter has been aptly christened An Turas, Gaelic for "the journey".

The distillation of elements is carried through to the palette of materials used. White walls, timber slats and slate flooring all have a rustic, timeless character that is set off by the sophisticated, contemporary glass box in its splayed galvanised steel frame. Finishing touches in the form of rough weathering and moss and lichen growth are now anticipated from Nature herself.

Not yet officially open, the tiny shelter has already scooped the gold medal for architecture at the Royal Scottish Academy Summer Exhibition in Edinburgh and has been nominated for two more architectural awards. Well might the local schoolmaster and client, Brian Milne, say: "It's just a glass box and two walls, but it's an awful lot more than that."