It’s home to Europe’s only population of wild monkeys and a labyrinth of tunnels that criss-cross through its limestone rock. Gibraltar could soon also be home to investment-grade wine from around the world, with work set to begin this month on transforming the rock into a state-of-the-art wine cellar.

“Our intention is to develop the largest underground wine storage facility in the world,” said Tracy Lee, of Gibraltar Wine Vaults. “We have the perfect conditions within the rock: 70 to 80% humidity, 13 to 14 degrees, no light, no vibrations.”

The facility will be housed within the territory’s extensive network of tunnels and vaults, built by the Royal Engineers prior to the second world war when British authorities were certain that an attack on Gibraltar was imminent.

Until recently, access to the tunnels was restricted. Lee learned of the existence and scope of the tunnels from her father, who served in the military. “In some of the huge tunnels in the Rock you can fit two 10-ton trucks next to each other. The chambers are the height of cathedrals. It’s extraordinary,” she said.

Several years ago she began wondering whether the limestone would lend itself to wine storage. The Ministry of Defence was handing over much of the network of tunnels to the Gibraltar government, and local authorities were keen to come up with novel uses for the space. Over the years, some of the vaults have been developed for storage or car parking.

The government was supportive of Lee’s idea, envisioning a project that could boost wine tourism in Gibraltar. All that was left was to prove that the limestone interior of the rock was the perfect place for wine to mature, said Lee. “We had to do a lot of tests to prove that my theory was correct.”

Construction is slated to begin at the end of the month and the facility is expected to be completed by mid-2017. The plans also include an interpretation centre exploring Gibraltar’s historical relationship with wine. “The wine culture in Gibraltar has existed since 1839,” Lee said.

The project is still in its early stages, but Lee said she has already had interest from clients around the world. The storage facility is expected to house more than £60m worth of investment wines in its first phase.

The second phase will allow the facility to house another 850,000 cases of wine, said Lee. “It’s limitless really. I mean there are 32 miles of tunnels in the Rock.”