A rare glimpse of Octavian Vaults's Corsham Cellars, where 5m bottles of fine wine are stored beneath the Wiltshire countryside
A case of Cos D'Estournel 2006, in Corsham Cellars. Photograph: Adrian Sherratt for the Guardian
You walk in through an anonymous modern office building, past suspicious guards and banks of security cameras, before descending 157 rickety steps into a wine lover's paradise. Around 5m bottles of fine wine, some worth thousands of pounds each, are neatly stacked in every nook and cranny of this vast subterranean complex.
This is Eastlays mine, in Wiltshire, once a source of honey-coloured stone, and now the place where the rich and famous hoard their most precious bottles of Petrus, Lafite or Latour. It is a secretive sort of place – the super-rich tend to insist on discretion – but with 2009 promising to be a particularly excellent vintage and lucrative markets booming in Asia, the Guardian was granted a rare glimpse of Octavian Vaults's Corsham Cellars.
"This is like a bank," said the operations director, Laurie Greer. "What we are storing here is liquid gold. Some of our customers buy wine as an investment. They don't want anyone else to know what they've got here. For others their wine is like an oil painting, it's their passion. They want to know it's safe here and being stored in the best possible condition."
After its supply of stone was exhausted, Eastlays was turned into a Ministry of Defence munitions dump. The size of 20 football pitches, it also served as a suitably gritty film set for scenes in the war classic The Guns of Navarone.
Greer says the 9 metres (30ft) of earth between the storage areas and the surface means it is possible to precisely control the temperature, humidity and the dew point to create the perfect conditions in which to store a bottle of wine. After all, it wouldn't do for a few drops of a £10,000 bottle of wine to evaporate or for the label to peel, or even for the crate to get mouldy.
Octavian has 180 trade customers and around 2,500 private clients from across the world. A third are from Asia, with China and India both swiftly growing markets. Greer will not name any customers, of course, but says they include showbiz and sporting stars.
Many clients like to visit their wine to check its condition. They too have to walk down the 157 steps, carrying an emergency underground escape kit if they want to go into the heart of the store. They can inspect the security measures if they choose, including motion-sensor beams used to protect bank vaults.
If they don't fancy the trip to Wiltshire, there are three photographic studios underground so that high-quality pictures of the wine can be taken at any time and sent to the client's desktop. And should they have a special occasion to celebrate, customers can ask for a crate or even single bottle to be sent anywhere in the world to impress their guests.
It's down to people such as Martin, one of the underground workers, to go and find the requested wine and bring it out. Has he ever dropped a bottle? "There are accidents from time to time," he says. "But we do our best."
Martin said workers did not like to know which were the really expensive bottles. "You get too careful. It's best to treat every single bottle with the same care."
Greer says the business, which employs 80 people at Corsham, has proved reasonably recession-proof. "People have still been buying and investing in wine. It's a long-term investment, they may store wine here for 20 or 30 years, so the recession hasn't been too bad."
With the experts saying the latest harvest may have been a classic, 2010 could prove to be an even stronger year.
Steven Morris: www.guardian.co.uk