The Restaurant Under the Sea / Financial Times

The century-old Lindesnes lighthouse has long been one of the biggest draws on the fractured southernmost coast of Norway. The stumpy red and white tower stands on a bare rocky outcrop overlooking the Skagerrak strait that divides Norway from Denmark, and the North Sea from the Baltic. It is ringed by the remains of German bunkers and gun emplacements from the second world war. In wild weather, which is common in this elemental part of the world, great waves crash over it, says Frank Otto Røiseland, one of Norway’s last two lighthouse keepers. On other days visitors can spot orcas, dolphins, seals and sea eagles. When I visited this week the sun shone, the sea was calm and the air so clear you could see for 20 miles.

From April 2 Norway’s oldest lighthouse will have a rival attraction. Seven miles up the rugged coastline, a large, modern concrete structure protrudes rather incongruously from an inlet ringed by low, wooded hills. It vaguely resembles the upturned end of a giant milk carton that has toppled off a rocky promontory into the deep blue water. This is Under, which claims to be the world’s biggest and Europe’s first underwater restaurant, and is about to open in the tiny coastal community of Båly.

Under, which also happens to be the Norwegian word for wonder, is not just physically incongruous. Båly is a five-hour drive from Oslo and more than 40 miles from Kristiansand, the nearest town or city of any size. It sits on a coastline that is sparsely inhabited except during those summer months when families arrive from Oslo and Stavanger to enjoy their cabins and boats and the great outdoors. The permanent population, such as it is, is known for being understated, conservative and devoutly Lutheran — and is certainly not used to flamboyant ventures like this.

The 70m krone (£6.2m) restaurant is the brainchild of two brothers, Stig and Gaute Ubostad, both in their early forties. Fourth-generation hoteliers, they bought Båly’s bankrupt Havhotell in 2014 and were drawn to the idea of building an underwater restaurant as a way of attracting guests throughout the year. Thus they have sunk — almost literally — all their capital into creating a restaurant that will, they hope, attract foodies from around the world. “We’re risking everything. If we weren’t a bit crazy it would be too big for us,” Stig candidly admits.

To realise their dream the brothers employed Snøhetta, the Norwegian architectural practice renowned for the iconic Oslo opera house, the Bibliotheca Alexandrina in Egypt, and the National September 11 Memorial in New York.

Snøhetta toyed with several designs before settling for one that is strikingly simple. Under essentially consists of a rectangular concrete tube, 112ft long and 40ft wide, with walls 1.6ft thick and slightly convex to withstand the strongest waves (oil industry experts with experience of North Sea oil rigs advised on its design). The 1,600-tonne tube was cast on a huge barge, towed into the inlet and lowered into position by a floating crane. Then it was sealed and the seawater pumped out.

While the upper end protrudes from the water, the lower end is bolted to the seabed 16ft beneath the surface so the tube slopes down at a 20-degree angle. From the outside the freshly cast concrete is a little jarring amid the natural beauty of the inlet, but Kjetil Trædal Thorsen, Snøhetta’s founding partner, says it will tone down as seaweed and mussels grow on its exterior.

Guests enter into a foyer panelled in smooth light oak, from where a widening staircase leads down to a champagne bar © Ivar Kvaal The interior, however, is a tour de force, and far more spacious than you would ever imagine from the outside. You reach the entrance across a 40ft gangway of galvanised black steel, and on stormy evenings diners will be drenched by the spray if they come unprepared. “In Norway there’s no such thing as bad weather, only bad clothing,” Trædal Thorsen chuckles.

At the far end of the gangway you enter a foyer panelled in smooth light oak. From there a widening staircase leads down to a mezzanine-level champagne bar with a narrow, floor-to-ceiling side window that is half above and half below the waterline. The view from the bar’s balcony is designed to elicit gasps — and it does.

Below is the restaurant, its dozen tables and minimalist furnishings bathed in aquamarine light from a huge glass window — 36ft across, 12ft high and nearly a foot thick. Beyond that window lies the sandy seabed with a few strategically placed boulders and strands of kelp waving in the currents. Most of the world’s other underwater restaurants are located in warmer waters full of tropical fish. The marine life here is somewhat less colourful and abundant — cod and pollock in winter, wrasse and mackerel in summer, sea urchins, the odd lobster and stone crab, a seal or diving eider duck if you are lucky. The restaurant uses lights, sound signals and occasionally food to attract more fish to the panoramic window, which is regularly cleaned by divers.

But diners should soon be distracted by the restaurant’s gastronomic offerings. Under will serve up to 40 guests an evening four nights a week. Its “immersion” dinner will last three to four hours, and consist of about 18 courses. Each course will be a surprise, and guests will be given written menus only as they leave.

Nicolai Ellitsgaard, the Danish head chef, intends to use local seafood and game. He and his kitchen staff will forage in the forests for mushrooms, wild garlic, herbs and berries, and along the seashore for shellfish, algae and edible seaweeds. He has been given free rein to experiment, he says. “Part of the deal is I can do whatever I want, but I promised the brothers not to be too weird.”

During a sneak preview of the restaurant this week, the Financial Times and other publications from the US, Russia and assorted European countries were given a couple of samples. They were certainly different. One was a crispy limpet “shell” made of potato and seaweed, filled with a mussel and limpet cream and served on a smooth stone. The other was the throat and roe of ling served with fermented butter and preserves on a small circle of Norwegian flat bread resting on a bed of shells.

Ellitsgaard readily acknowledges that ling is a cheap fish whose head and roe are normally thrown away. “At the fish market they said what the f*** do you want this for. It’s garbage,” he says. “I said ‘give me time and I’ll show you’. The head is tastier than the rest of the meat.”

The restaurant’s official launch on Wednesday was big news in relatively sedate Norway, and broadcast live on television. The publicity has ensured that Under is almost completely booked until late September, although dinner will cost an eye-catching 2,250 krone (£200) a head plus another 1,500 krone or so for the wine-pairing menu.

Trædal Thorsen, the architect, calls the Ubostad brothers “visionaries with their feet on the ground”, but whether Under will prosper once the novelty has faded depends largely on whether it can attract an international clientele to this remote location at the end of Norway. “We have really high ambitions,” Ellitsgaard says. “It’s dangerous to talk about Michelin stars but it would be a dream come true. This place really deserves it.”

The Norwegian airline Widerøe launched direct flights from London Stansted to Kristiansand last year, and there are plenty of ways to fill the rest of a short break in the area. There is the beautiful coastline, dotted with islands, and the pristine rivers, lakes and forests of birch and spruce, sprinkled with traditional red wooden farmhouses, of the interior. There is ample opportunity to cross-country ski in winter, and to raft, canoe, fish and hike in summer.

A world-class performing arts centre, with theatre, concert hall and opera house, opened on the waterfront in Kristiansand in 2012. Beside it a giant 1930s grain silo is being converted into a museum and gallery that will house the world’s largest collection of 20th-century Norwegian art.

The Ubostad brothers obviously hope that visitors will stay at their comfortable, modern Havhotell, a few hundred yards from the Under restaurant, but my personal preference would be to rent the old wooden lighthouse keeper’s house at Lindesnes. It is simple and spartan with a wood stove for heating and old black-and-white photos on the walls. In bad weather you will fall asleep to the sound of waves battering the building as the revolving beam from the lighthouse offers solace to ships out to sea. In good weather you will enjoy sublime views capped by spectacular sunrises and sunsets. Being under the ocean has its attractions, but on balance I would rather be surveying it in the bracing air above.