Deep in the Lizard countryside lurk the remains of a high-security military facility now the unlikely home of culinary innovation.

Hidden at the bottom of a no-through road on the outskirts of Coverack, few will have had cause to pass the old nuclear bunker or even know of its existence, save the handful of locals.

At first glance the mass of concrete appears abandoned - a faded reminder of a time when the threat of nuclear war loomed and the "four minute warning" was at the forefront of the nation's mind.

Built as a sealed unit, with views of the sea on three sides, RAF Treleaver's radars were designed to provide four minutes of warning on any Soviet Union bombers attempting to arrive in the country via a circuitous route across the Atlantic, before being locked down as a war room for military top brass to retreat to and run the country from, in the event of a Cold War nuclear attack.

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The 'war room' as it would have looked in the bunker in the 1950s. Photo: Artisan Malt Vinegar

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How the lower part of the bunker looks today

Today, however, the former 'ground control and deception' station is the unexpected home of Artisan Malt Vinegar - an award-winning vinegar produced by father and son team Mark and Geoff Nattrass.

Mark said: "It's amazing how many people don't know we're here."

Leaving his life as a lawyer in Birmingham nearly 20 years ago, Mark arrived in Cornwall "not having a clue" what he was going to do.

He initially set up the Lizard Ales micro-brewery on an industrial estate in St Keverne, producing the An Gof, Frenchman's Creek and Lizard Bitter bottled ales that continue to be sold through Asda. The business quickly outgrew the site and a surveyor friend suggested the abandoned bunker, left derelict since the MoD moved out.

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Mark Nattrass is producing award-winning vinegar from an old nuclear bunker

With no electricity and just a few bales and pieces of farm equipment lying around it was not an obvious choice but structurally sound, and a few renovations saw them move in in 2008.

As it happened, the bunker was the perfect place. Built to withstand a nuclear bomb, with blast doors at each end, the walls and ceilings are super-reinforced, one-metre thick concrete embedded with a metal framework. As such, the temperature remains pretty much constant throughout the year - ideal conditions for producing ale.

These days the focus of the business is very much on the vinegar - something that Mark knew nothing about producing when he started, and it seemed very few other people did either.

"Suddenly micro-breweries were everywhere. I looked for something else I could do and came up with vinegar, which nobody else does.

"It took quite a long time to figure out how to make it. With beer it's easy because there are lots of breweries and you can go on courses, but with vinegar there's nothing," he said. "I knew that it was either a really good idea or a really bad idea."

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Mark Nattrass shows the initial fermenting process

With no recipes, or even any equipment to buy, Mark took inspiration from the world-famous vinegar producers of Spain and Italy, using high quality ingredients and adapting brewing equipment to what was needed as he followed the process.

It took took two or three years to get the formula right but the end result was a hit.

It won Taste of the West gold awards in 2014, 2016, 2017 and 2018, and is thought to be the only malt vinegar to ever win a Great Taste Award, in 2013 and 2017.

Its main customers are high end chefs, with Michelin-starred chef and Great British Menu semi-finalist Josh Eggleton recently publicly endorsing it, while locally Janes Fish and Chips use it in their restaurant and takeaway.

It marks a renaissance for the building that, in the event, saw a less than illustrious lifespan. Building work started in the late 1940s, but progress was so slow that by the time it was finished in 1956 technology had moved on to such an extent that it was all but obsolete when it opened.

It remained a working operation for two years, before it was decommissioned in 1958, with questions even raised in parliament over it.

Falmouth Packet:

Mark Nattrass is producing award-winning vinegar from an old nuclear bunker