This may look the set of a Doctor Who episode – but its original purpose could not be more serious.
The bunker was designed to withstand a nuclear strike when people lived in constant fear of annihilation.
After the threat from behind the Iron Curtain began to fade, this sinister Cold War relic 100ft under Corstorphine Hill was almost forgotten.
Its enemies turned out to be much closer to home – vandals, thieves and a fire that ripped through its abandoned tunnels in the early 1990s.
But now the Barnton Quarry, the only surviving example of this type of bunker in the UK, is set to open as a landmark museum as early as 2019.
The former command centre will look as it did in the early 1950s thanks to a dedicated band of volunteers, including a core team of “bunker-obsessed” history fans, who are determined to revive its fortunes.
They have been working on the underground project for the last four years – salvaging fixtures and fittings, sand-blasting rust-caked metal, and scouring graffiti in an effort to return it to its eerie Cold War glory.
The team has sourced equipment and materials from other bunkers, cleared thousands of tonnes of debris dumped by fly-tippers and restored power.
Electrical engineer Grant More, programme manager of the Barnton Quarry Restoration Project, says: “The site had lain derelict since 1993. There was about 2000 tonnes of fly-tipping down there and we had to dig our way in.
“It has been pillaged and burnt out and completely destroyed. It was a burnt-out shell but now we are halfway through the project.”
Without these volunteers, aged from 18 to 80, the multi-million-pound project would be faced with an unbridgeable funding gap.
From specialist riggers to enthusiastic amateurs, it is difficult to overstate the work put in by the volunteers since work started.
“These guys are unbelievable,” adds Grant, who, like many of those working on the project, also holds down a full-time job.
The group has studied archive photos in an effort to make their restoration as authentic as possible – even down to the type and colour of paint used.
Volunteers have also consulted RAF experts and historians and quizzed some of those who worked in the bunker.
The work has been bankrolled by James Mitchell, who also owns Scotland’s Secret Bunker in Troywood, Fife, a successful visitor attraction which opened to the public 20 years ago.
A portion of the takings from that museum has been put into the Barnton Quarry Restoration Project.
When the Edinburgh bunker opens to the public as a visitor destination, profits will be used to maintain the building, conserving it for future generations to enjoy.
When it is finished, Barnton will include interactive displays, guest exhibitors and possibly holographic projections.
Grant says: “We want to restore the site to enable us to open an education centre, allowing visitors to learn about what really went on in a government bunker during this time. It’s an astonishing place and most people don’t even know it’s there.
“Our first aim is the preservation of this unique building right under our feet for future generations.
“But we also want to use it as a platform and an education centre because we are all passionate about Cold War history, which is not extensively taught in the Scottish syllabus.”
The restoration team also plans to restore and display the communications technology that existed at the time the bunker was created.
The bunker, built in 1952, had many thousands of phone lines, a full telephone exchange and a room full of teleprinter equipment to ensure that officials could continue to communicate if the worst happened.
It was used as the Sector Operations Centre for the Caledonian Sector, receiving information from radar stations across Scotland.
The 37sq ft bunker was one of four nuclear command centres UK and the nuclear response nerve centre for the whole of Scotland.
The staff at RAF Barnton Quarry were there to protect Scotland from attack by Russian long-range nuclear bombers up until 1960 when it was decommissioned.
But with the advent of nuclear missiles, the bunker later became one of 14 Regional Seats of Government (RSG) from which officials would run the country in the event of an attack.
Boasting reinforced concrete 10ft thick and metal blast doors, it was equipped to hold hundreds of staff in complete isolation for a month if the Cold War turned hot.
Manchester-based photographer Andrew Brooks visited the site five years ago, before restoration work had started.
He hopes to create an exhibition called Secret Cities Edinburgh featuring photographs of inaccessible and unusual spaces from inside the city.
Recalling his time at the Quarry, he said it was “probably one of the most intense photographic shoots” he had worked on. “The whole place was in ruin, with fire blackened walls and years of damage. It felt like the set of a zombie movie.”