At long last Gleneagles Townhouse has thrown open its doors with an invitation “to gather and be glorious”. The grand St Andrew’s Square address is part of the fabric of Edinburgh’s New Town.

It’s even mentioned in Robert Louis Stevenson’s 1886 novel Kidnapped as the British Linen Company and later was the most impressive Bank of Scotland branch.

Now, emerging from the shadows of dusty bank desks and five years of painstaking polish and renovation by Ennismore Design Studio, the social butterfly younger sister venue of Gleneagles Hotel is ready to dazzle.

The rooftop members’ bar Lamplighters looks stunning, though you’ll need a private membership (*or be a hotel guest) to experience it.

Thankfully, the all-day restaurant The Spence is no consolation prize. Housed in what was the grand banking hall, all eyes are immediately drawn to the intricate domed ceiling.

The etched glass has been replaced in the cupola, and from it light bounces over gilded edging, intricate cornicing and bold modern art.

There’s a speakeasy, prohibition era feel to The Spence, with fringed lampshades, low-slung mint green banquettes, big plants and scalloped pink velvet armchairs, perfectly complementing the pale pink marble of the columns.

The vast room is cleverly divided into an abundance of cosy corners with a curvaceous central art-deco bar and open kitchen, without losing the grandeur of the columns and beautiful domed ceiling. It’s glamorous, gorgeous and a lot of fun.

I like a menu with a suggested cocktail, and am only too happy to try the Spagliato, with vermouth, Cocchi Torino, Aperol and Cremant.

It’s like a grown-up Aperol spritz:  zesty and refreshing. My driving pal opts for the ‘Atomic’, which she reports has all the pleasing punchiness of an alcoholic cocktail, always a good sign.

Running the kitchen is head chef Jonny Wright, bringing his culinary talents back to Scotland after a number of senior roles at top London restaurants, including Michelin-starred Evelyn’s Table.

The National:

At The Spence produce is king with impeccably sourced Scottish produce with a modern twist. The menu is flexible, with plenty to entice young, hip customers without alienating Gleneagles’ core clientele.

There’s no pretension with the well-trained sparky staff; they know many people will be here for special occasions and bring their A-game to every table.

We choose a couple of pre-starter snacks to go with the cocktails. I can never say no to an oyster and in this setting surely they are compulsory? I’m intrigued by the lime and jalapeño ceviche, which turns out to be oysters topped with a mound of green crushed ice.

With a slurp, the cold rather than the chilli hits the hardest – like I’ve taken a shot of a jalapeño slushie.

The National:

Hidden beneath, the creamy oyster feels like an afterthought not the star attraction. Lesson learned, stick to mignonette next time.

Our other pre-starter snack is more successful: Faroe island bacalao beignets, warm doughnuts of salt cod and potato, pulled apart and dipped into a piquant piri-piri dip. They are perfect for sharing but we both wish we didn’t have to.

My starter is a crab crumpet, a generous pile of tender sweet crab on a warm, bouncy crumpet with spiced butter. Over the crab are dots of yuzu, cutting through the rich crab and paper-thin slices of radish.

Across the table, baby artichokes are also a hit, dunked into a swirl of hazelnut ricotta with lemon.

I’m delighted to see sustainable success story Isle of Gigha halibut on the menu and it doesn’t disappoint.  A generous fillet on the bone, in a pleasing pool of buttery sauce and a tangle of sea greens, lets the quality of the fish shine through. The side dishes are all appealing.

The National:

We opt for bitter leaves, a sculptural bowl of radicchio with anchovies and a flurry of parmesan on top. Roast Jersey royals are perfect with my buttery fish.

Somehow I manage cheese, and it’s superb: Ailsa Craig goats cheese, Blue Murder, Minger, Corra Linn and St Andrew’s Cheddar. A dream team, with oatcakes, charcoal crackers and quince gel. A swiped taste of the creamy buttermilk panna cotta confirms the puddings are just as good.

Opening a city hotel is bold for Gleneagles, a brand with the Perthshire countryside embedded in its DNA.

It has proved a genius move.

It’s bright, bold, younger and more easily accessible, with the same enduring commitment to hospitality, quality and style. As hoped, Gleneagles Townhouse is a spectacular addition to the city.

www.gleneagles.com/townhouse