The unexplained disappearance of a trio of lighthouse keepers has been one of Scotland’s biggest mysteries for more than a century. In December 1990, three men working on the Eilean Mòr outpost to the west of the Outer Hebrides vanished without a trace.

Gerard Butler, Peter Mullan and Connor Swindells star in The Vanishing (Image: Daily Record)

A ship passing the Flannan Isles noticed that the light was out and called a relief crew after docking on the mainland. They came ashore and discovered that the maintenance workers were gone. However, nothing else appeared to be amiss, save for one solitary, upturned chair.

The strange and unanswered story has puzzled experts for decades and inspired poems, a song by Phil Collins’ Genesis, a Doctor Who episode, and one of comedy duo Greg Hemphill and Ford Kiernan‘s most famous sketches.

And interest in the mysterious tale was reignited in 2018, when it became the focus of a blockbuster movie starring Gerard Butler and Peter Mullan. The two Scottish stalwarts, alongside Connor Swindells, play lighthouse keepers James Ducat, Thomas Marshall, and Donald MacArthur, respectively, in The Vanishing.

It was filmed in the Mull of Galloway in 2017, with Butler saying shortly before the movie’s release: “I loved being back in my homeland Scotland to shoot this beautiful, haunting, atmospheric thriller.”

During the film, a stranger washes up on Eilean Mòr, the largest of the Flannan Isles, along with a mysterious chest. Thinking he’s dead, they take the chest, but the stranger wakes up and is killed in a fight.

The Vanishing is based on the true story of the Flannan Isles Lighthouse keepers (Image: Daily Record)

While they decide what to do with the treasure chest, a boat full of strangers arrives on the island looking for answers, sparking a deadly battle.

The true story behind the trio’s disappearance still remains unknown. They reported for duty on December 7, 1900, with MacArthur a stand-in for William Ross, who was ill.

Eight days later, the passing steamer Archtor, bound for Edinburgh from Philadelphia, noted that the light was not burning and raised the alarm when she docked five days later. On Boxing Day, relief keeper Joseph Moore arrived and discovered the eerie scene, with unmade beds, missing oilskins and the single upturned chair.

Gerard Butler plays pricipal keeper James Ducat (Image: Daily Record)

There were no signs of trouble and no clue as to where the men could have gone. The logs had been kept up to date by the three men until December 13 but they did find a journal noting activity on the morning of December 15 – what happened later that day remains a mystery.

Moore and two volunteers reignited the lighthouse and kept it burning until investigators arrived. In a report to the Northern Lighthouse Board on December 28, Moore wrote: “I went up and on coming to the entrance gate, I found it closed.

“I made for the entrance door leading to the kitchen and store room, found it also closed and the door inside that, but the kitchen door itself was open. On entering the kitchen, I looked at the fireplace and saw that the fire was not lighted for some days.

“I then entered the rooms in succession, found the beds empty just as they left them in the early morning. I did not take time to search further, for I only too well knew something serious had occurred. I darted out and made for the landing.

“Mr McCormack (a volunteer) and myself proceeded to the lightroom where everything was in proper order. The lamp was cleaned. The fountain full. Blinds on the windows etc.”

Moore believed the keepers may have been attending to repairs or a rescue by the shore when they were swept away by a giant wave.

A woman in Uig, on the west coast of the Isle of Lewis, reported seeing a huge wave crashing ashore on the day of the disappearance, sweeping away her washing line.

In the film, a man washes up on Eilean Mòr – but the true story remains a mystery (Image: Daily Record)

The Flannan Isles mystery has been the subject of numerous works of art in the many years since. Poet Wilfrid Wilson Gibson penned Flannan Isle in 1912, while Genesis recorded The Mystery of the Flannan Isle Lighthouse in 1967. A decade later, Doctor Who serial Horror of Fang Rock contained many elements inspired by the disappearance, followed by chamber opera The Lighthouse, from 1979.

Fans of Hemphill and Kiernan’s work will likely recall their Chewin’ The Fat lighthouse keepers at the fictional Aonoch Mhor site. Their sketches were among the most popular during the show and spawned the legendary catchphrase: “Gonnae no’ dae that?”