It is the unlikeliest of Aladdin's Caves. Dimly lit by orange bulbs and buried 15 metres beneath a nondescript Hong Kong hillside, it is coated with 2.5 metres of reinforced concrete encasing a half-inch shell of steel that might comfortably withstand a nuclear onslaught.

As the reinforced door at the end of an underground tunnel creaks open, all there is to see in the meticulously climate-controlled 1,000 sq ft space is row after row of functional metal shelving with cardboard boxes and wooden crates in orderly piles reaching almost to a ceiling of cold steel beams and huge rivets.

Peer through the gloom at the nearest crate, however, and the dazzling extent of the hidden treasure within this former military bunker takes shape in the form of a six-litre Methuselah of Romanée-Conti 1989 with a handwritten label on it recording the price it has just fetched at auction: HK$700,000.

That is the value of just one of the 25,000 bottles stored in this single bunker at Crown Wine Cellars, in Shouson Hill, the first wine storage facility in Hong Kong created from a blast-proof munitions storage facility. The bunker was built in the 1930s by the British Army's Royal Engineers.

"We have more than one million bottles of wine," says the company's managing director and co-founder, Gregory De'eb, referring to the stock held in eight underground bunkers in Shouson Hill and a larger, modern facility in western Kowloon. "Conservatively, [the stock] is worth more than HK$1 billion.

"You are looking at at least HK$1,000 a bottle. At the top end, we have two [of the] most expensive [bottles] ever sold in one of our vaults … 1869 Chateau Lafite standard-sized bottles [750ml] sold by Sotheby's in October 2010, and they achieved US$232,692 per bottle."

The extraordinary bounty here reflects a phenomenon of the past decade that has seen a significant proportion of the world's finest wines migrate from Europe and the United States to Hong Kong.

More than 40 other wine-storage companies have opened their doors since Crown Wine Cellars pioneered the paradigm shift from Hong Kong collectors buying wine and storing it overseas to buying it and storing it here, where it can be drunk and enjoyed.

Despite a recent dip in the global wine market, triggered in part by the crackdown on corruption in the mainland, the world's biggest buyer of fine wines, the Hong Kong market, has remained robust and continues to set records.

Hong Kong has overtaken London and New York as the wine auction capital and sells more fine wine at auction than the rest of the world combined. In October, Sotheby's here sold a 114-bottle set of Romanée-Conti wine for US$1.6 million, the most expensive wine lot ever sold at auction. That translates to US$14,121 a bottle or US$1,700 a glass. That collection is now stored at Crown Wine Cellars.

Robert Sleigh, head of Sotheby's Wine, Asia, says the Asian wine market has developed as much in the past five years as the world wine market has in the past two centuries.

"Like everything that happens in Asia, it is at warp speed," he says. "It is a very sophisticated market. It is a much more educated market than a few years ago. You have more depth and more reason in there and it is also broadening out."

With local collectors - estimated to account for about 60 per cent of those who store wine in Hong Kong - now able to keep their wine close at hand, buyers are developing self-financing cellars, he says.

"You buy five, drink three and the two left over will pay for the three you drink [when sold], if you are lucky," explains Sleigh, who claims the Hong Kong market is now "driving the world wine business".

Wine began flooding into Hong Kong as soon as the first sophisticated storage facilities became available, mainly because the city already had a huge community of collectors - including senior government officials - who, for decades, had bought and stored wine overseas.

"All those great wine collectors who had collections built up over 40 years had incredible knowledge, incredible stocks and, if anything, were way ahead of their European counterparts," says De'eb, a South African former diplomat who teamed up with the head of Crown Worldwide, Jim Thompson, to create Crown Wine Cellars in 2001.

"When we opened for business, it gave them the first opportunity to bring the wines back - and we had this as a bonded location, so they could bring the wines out duty free. For the first time, they could bring over cases and just extract a single bottle and only pay duty bottle by bottle."

Encouraged by the slashing of the 40 per cent duty to zero in 2008, so much of the world's finest wine has moved eastwards, local and mainland collectors now constitute the majority of both sellers and buyers.

"There are now Hong Kong people selling to Hong Kong people or [mainland] people selling to Hong Kong people and Hong Kong people selling to mainland collectors," says De'eb. "All the stock stays and exists in Hong Kong.

"People in Hong Kong know their wines. The days of people saying they still need time to learn and time to mature do not apply to Hong Kong collectors any longer. It is now very much the case that it does not apply to mainland collectors, either. I do not know of a single mainland collector who uses my company who could, in any way, be considered naive.

"They know what the international market is, they know what they are prepared to pay and it is like the contemporary Chinese art market - people are very savvy and they have become very savvy very fast."

Hubert Li, managing director of the Hong Kong Wine Vault, which began business six years ago and now has 82,000 square feet of storage and more than 500 customers with 1,000 bottles or more, says his customers typically include bankers and lawyers on Hong Kong Island and doctors and entrepreneurs in Kowloon.

"When we first started our business, we were serving ourselves and our friends," Li says. "We weren't expecting demand to be so great.

"Hong Kong has become a pretty mature and sophisticated drinkers' market … People drink very unique stuff. China, on the other hand, is very different. A few years ago they were all buying Lafite. Now they are all buying Romanée-Conti. They are very focused on the big labels."

The crackdown on corruption in the mainland has dented but not halted the wine market's growth, Li says.

"It is no secret that since the [implementation of the] Chinese government's policy to restrict government expenditure, people have been buying much less of the very expensive wines. They don't drink them and open them in public places. There are fewer mainland buyers on the floor at auctions. But the rarest wines will always [be in] demand, especially [by] the very serious collectors for whom money is not an issue.

"Demand is still there but it is not as crazy as it was three years ago."

The soaring price of wine as an investment has inevitably created security issues.

"If you have people inside your company, there is going to be the inevitable opportunity to pick up a bottle of wine and walk out," says De'eb. "If that bottle of wine is HK$1,000 you can say, 'Damn, that was naughty', but when that bottle is US$184,000, it's not so funny."

So, for its most valuable bottles, Crown has had fitted a vault built to the same security standards as those used in banks and claims to be the only wine storage company in the world to use such a facility.

"We have had losses - nothing that's ever given us a heart attack but only because we've been so pedantic about our security," De'eb says.

One scenario the company may not have anticipated but was nevertheless prepared for was when the estranged wife of a collector used his membership details to try to relieve him of a valuable bottle of wine after their marriage had broken down.

"Fortunately it was nipped in the bud when we rang the delivery address and found it wasn't one of the registered addresses for that member," says De'eb. "The husband was ballistically angry with us until we explained to him that if you shared those details with someone else, it wasn't actually our responsibility."

Hong Kong's capacity to snaffle up an even greater share of the world's finest wines continues to grow as tens of thousands more square feet of storage space are created each year by a growing number of companies catering to every class of collector.

"If you add them all together we probably have more than 500,000 square feet," says De'eb. "Purely in terms of [storage] volume, the UK has to be two to three times our size but they have been doing it for 200 years and I figure that, within 10 years, to be a third the size of the UK is pretty impressive."

When it comes to the world's finest and costliest wines, however, an even higher proportion is already in Hong Kong - many of them in an Aladdin's Cave where the treasure trove grows larger, richer and more exotic by the month.


How Hong Kong's wartime bunkers were turned into wine cellars

The underground bunkers in which Hong Kong's first wine storage facility was built have a unique place in the city's history: they were the last corner of the territory to hold out against the Japanese invaders in 1941.

Built by the British Army only a few years earlier, the bunkers in Shouson Hill held the munitions for Hong Kong's defence and were fiercely guarded by a tight-knit band of Punjabis, Canadian Grenadiers, British Royal Engineers and local Chinese soldiers.

Hong Kong surrendered to the Japanese on Christmas Day 1941 but the invaders failed to locate the munitions area known locally as "Little Hong Kong" - confusingly, perhaps deliberately so, the same name in Cantonese for nearby Aberdeen. Two days later, a Japanese commander finally located it and approached with a small group of soldiers and a translator.

Captain Suzuki found himself confronted by a defiant British commander, Major Dewar, who told him he had wired all 24 bunkers to a central detonator.

"The Japanese were shouting, 'Hong Kong has surrendered - you are surrounded,'" says Crown Wine Cellars managing director Gregory De'eb. "Major Dewar told them he had a detonator linked to 24,000 square feet of explosives and told them, 'Bugger off or I'll blow the place up.'"

According to a British witness to the confrontation, a wry smile spread over Suzuki's face when Dewar's warning was relayed to him and he responded by saying to his translator: "Tell him I'll give them an honourable surrender."

With those words, the stand-off was defused and the defenders stood aside.

"If Major Dewar had actually pushed the detonator, there wouldn't be a Shouson Hill today," says De'eb.

Almost 60 years later, the idea of converting the eight bunkers (four pairs) that are still serviceable into wine storage cellars was dreamed up by the chairman of removal company Crown Worldwide (which will celebrate a half century in business on Wednesday), Jim Thompson, and De'eb in response to government suggestions that Hong Kong could become Asia's wine trading hub.

"Both Jim and I have a love of history and heritage," says De'eb. "When we found the bunkers, there was a shared desire to see them not only preserved, but revitalised." Up until 2003, the bunkers were being used by the Geotechnical Department for rock core storage.

"We wanted to create a living museum that would stand out as an icon to those who sacrificed everything so that we could enjoy modern-day Hong Kong.

"It is so critical to preserve this part of our history and, because it is a shared history, it really goes to the essence of what Hong Kong is about - a Chinese city with this amazingly colourful inter-related background that brings in people who, in many instances, like the Canadian Grenadiers, had never even heard of Hong Kong before.

"These people landed here and within a very short space of time they were dying for the place. And I think that is the important message to get across. It is one thing people coming here in a modern sense and making as much money as they can and then turning around and high-tailing it out of here at the first sign of any difficulty. These guys were the absolute opposite - people who came here and gave up their lives for a place they essentially were not a part of."

The creation of the wine storage facility has itself become a piece of Hong Kong history, spawning a new industry for the city.

"This was Hong Kong's first professional wine cellar," says De'eb. "It was the start of the government's drive to make Hong Kong the Asian regional wine centre."

Red Door News Hong Kong