HELSINKI (AFP) - Divers have found bottles of champagne some 230 years old on the bottom of the Baltic which a wine expert described Saturday as tasting "fabulous".

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Thought to be premium brand Veuve Clicquot, the 30 bottles discovered perfectly preserved at a depth of 55 metres (180 feet) could have been in a consignment sent by France's King Louis XVI to the Russian Imperial Court.

If confirmed, it would be by far the oldest champagne still drinkable in the world, thanks to the ideal conditions of cold and darkness.

"We have contacted (makers) Moet & Chandon and they are 98 percent certain it is Veuve Clicquot," Christian Ekström, the head of the diving team, told AFP.

"There is an anchor on the cork and they told me they are the only ones to have used this sign," he said, adding that a sample of the champagne has been sent to Moet & Chandon for their analysis.

The group of seven Swedish divers made their find on July 6 off the Finnish Aaland island, mid-way between Sweden and Finland, near the remains of a sailing vessel.

"Visibility was very bad, hardly a metre," Ekstroem said. "We couldn't find the name of the ship, or the bell, so I brought a bottle up to try to date it."

The handmade bottle bore no label, while the cork was marked Juclar, from its origin in Andorra.

According to records, Veuve Clicquot was first produced in 1772, but the first bottles were laid down for 10 years.

"So it can't be before 1782, and it can't be after 1788-89, when the French Revolution disrupted production," Ekstroem said.

Aaland wine expert Ella Gruessner Cromwell-Morgan, whom Ekstroem asked to taste the find, said it had not lost its fizz and was "absolutely fabulous".

"I still have a glass in my fridge and keep going back every five minutes to take a breath of it. I have to pinch myself to believe it's real," she said.

Cromwell-Morgan described the champagne as dark golden in colour with a very intense aroma.

"There's a lot of tobacco, but also grape and white fruits, oak and mead," she said of the wine's "nose".

As for the taste, "it's really surprising, very sweet but still with some acidity," the expert added, explaining that champagne of that period was much less dry than today and the fermentation process less controllable.

"One strong supposition is that it's part of a consignment sent by King Louis XVI to the Russian Imperial Court," Cromwell-Morgan said. "The makers have a record of a delivery which never reached its destination."

That would make it the oldest drinkable champagne known, easily beating the 1825 Perrier-Jouet tasted by experts in London last year.

Cromwell-Morgan estimated the opening price at auction of each bottle at around half a million Swedish kronor (53,000 euros, 69,000 dollars).

"But if it's really Louis XVI's wine, it could fetch several million," she added.

The remaining bottles, which could number more than the 30 uncovered by the divers, will remain on the seabed for the time being. Their exact location is being kept secret.

Meanwhile local authorities on Aaland will meet Monday to decide who legally owns the contents of the wreck. The archipelago at the mouth of the Gulf of Bothnia belongs to Finland, though it enjoys autonomy from Helsinki and its inhabitants speak Swedish.