Is this new British Airways airport lounge the best in the world?

Airport lounges have been going downhill.

They used to be exclusive retreats, for which passengers would dress up. But over the past few years, dull mass-appeal lounges that almost anyone can access have been spreading unchecked around the terminals of the world.

Happily, British Airways appears to be trying to reverse this trend with two new lounge openings in Dubai and Miami, which evoke the glamor of yesteryear and, according to the carrier, will serve as the vision for future lounge developments.

The one in Miami, above Terminal E — the departure point for destinations that include London, Madrid, and Doha — is the first dedicated BA lounge in the airport for decades. And as I discovered when I visited for the launch on Friday, it was worth the wait. It’s absolutely stunning — like being inside a five-star hotel.

The airside salon is for international business and first-class flyers with BA and Oneworld partner airlines, such as American Airlines and Qatar Airways. What they’ll discover inside is a seductive homage to Miami’s Art Deco heritage — the city has over 800 buildings in this style — with the design incorporating elegant geometric patterns and curves, and lavish materials.

There are also some clever nods to Miami’s beach culture (spot the deckchair stripes in the bathrooms) and the London Underground (look out for the cushions upholstered in “Tube train” fabric).

The designers have woven in some BA branding, too.

For example, the airline’s ribbon-like logo is subtly repeated on flooring that wraps around the bar — a gold-hued showstopper, complete with sexy red barstools and airfield views.

The bartenders move with purpose and can rustle up almost any potion you desire. I can vouch for the very refreshing Nojito mocktail.

The food offering is also excellent.

The main dining space, with its plush booths, is an upscale take on the classic American diner. The self-serve dishes here are Michelin Guide-worthy, ranging from filet mignon with potato puree and wild mushrooms to seared South Florida flounder fish with fried capers and rice. There’s a fun Pick 'n' Mix candy section, too.

First class passengers are invited to enjoy an elevated a la carte dining experience in the Concorde Dining Room, a mini version of the flagship lounge in Heathrow, and something of a haven within a haven.

Dishes include wagyu beef strip loin with roasted trumpet mushrooms and a truffle reduction; tri-color cauliflower korma; and The Concorde Burger, with Applewood bacon, thick-cut fries, and Shropshire blue cheese.

To wash it down, there’s Pommery Cuvée Louise 2005 Champagne and fine wines such as Nielson Pinot Noir from Santa Barbara County and J.M. Boillot Montagny Premier Cru white Burgundy.

With hunger and thirst sated, chic armchairs and comfy banquettes beg to be lingered in. And there’s plenty of room to manoeuvre — the lounge covers 13,000 square feet, about the size of an Olympic swimming pool, and has capacity for 230 people.

To take the pampering up a level, freshen up in one of the two shower suites — they’re beautiful, and feature glorious oversized rainshowers.

Need to work? USB ports and power sockets are liberally peppered throughout; the wifi is military-grade (I ran a speed test, and the needle hit the maximum thresholds for uploads and downloads). If single-minded concentration is paramount — or you want to scream in frustration at news of a flight delay — soundproofed “focus booths” are available.

The lounge doesn’t cater for children — there are no play areas or games for little ones (though the airfield views kept one toddler occupied on my visit). However, for adults, it’s a seriously classy place to wait for a flight, a ravishing retreat that I predict will become a signature Miami Airport experience.

The Miami lounge is open to British Airways customers travelling in Club World (business class) or First; British Airways Club members with Silver status and above; and long-haul business and first-class customers with Oneworld partner airlines, including American Airlines and Qatar Airways. Long-haul Oneworld customers with Sapphire status and above are also eligible.