What Was the Flannan Isle Mystery and What Happened to the Missing Eilean Mor Lighthouse Keepers?

In December 1900, three Flannan Isles lighthouse keepers disappeared without a trace. The question of what happened to them would become one of Scotland’s most intriguing mysteries. So, has the Flannan Isle mystery been solved? Read on to find out.

10 June 2022

Some time on 15 December 1900, the three keepers of the Eilean Mor Lighthouse disappeared. Nothing in the building was amiss. The kitchen was clean. The doors closed. But there was no sign of Thomas Marshall, James Ducat and Donald MacArthur.

Known as the Flannan Isles Lighthouse mystery, the story has been the subject of investigation, speculation and rumour. It has inspired songs, poems, documentaries and a 2019 dramatisation.

The Flannan Isles

The Flannan Isles Lighthouse might be more precisely called the Eilean Mor Lighthouse. It was one of the first structures ever built on the island of Eilean Mor. Indeed, prior to its construction, the last signs of human habitation dated back to ancient times. This is perhaps due to the extreme isolation of Eilean Mor, not to mention its size. Located some 80 miles away from the Scottish mainland, in the Outer Hebrides, Eilean Mor is one of seven tiny, rocky specks of land together known as the Flannan Isles. Named after St Flann, this collection of islands in the Scottish archipelago is sometimes called the Seven Hunters.

It took around four years to build the Flannan Isles Lighthouse and it was first lit on 7th December 1899. Just over a year later, it would become the scene of one of Scotland’s most baffling mysteries.


Lighthouse and sea mist (Photo: 2c image via Getty Images)

On the night of 15th December 1900, a transatlantic steamer called Archtor was heading to the port of Leith when it passed the Eilean Mor Lighthouse. The crew noted that no light was emitting from there and reported as much to the Northern Lighthouse Board on docking three days later.

On 26th December 1900, the lighthouse tender ship named Hesperus arrived at Eilean Mor on a routine relief visit. Hesperus’ crew found the lighthouse in darkness, with no flag flying.

Hesperus made several attempts to elicit a response from the Flannan Isles Lighthouse keepers, including sounding the ship’s horn multiple times and firing a rocket. When there was still no reply, the Master of the Hesperus, Captain Harvey, sent the relieving keeper, Joseph Moore, in a boat to the island.

The Missing Flannan Isles Lighthouse keepers

Beam of light shining into stormy ocean (Photo: John M Lund Photography Inc via Getty Images)

Moore was confronted with an eerie scene. The lighthouse was deserted, with no sign of the Flannan Isles Lighthouse keepers. Three keepers had been on duty at the Eilean Mor Lighthouse, Principal James Ducat, 43, 2nd Assistant Thomas Marshall, 40, and Occasional Keeper, Donald McArthur, 28. McArthur was a replacement for 1st Assistant William Ross, who was on sick leave.

The Flannan Isles Lighthouse itself was in good shape, with the lamp clean, the blinds on the windows and the fountain full. Pots and pans were scrubbed and the beds were just as they were normally left in the mornings. Of the gates and doors, only one in the kitchen was open.

Writing on 28th December 1900, Moore concluded, “I only too well knew something serious had occurred.”

Alarmed, he returned to Hesperus and came back to the lighthouse with three more crewmen. They confirmed his observations.

So, what had happened to the Eilean Mor Lighthouse keepers? An investigation was launched. Three men, including Moore, were left to run the Flannan Isles Lighthouse. They also took the opportunity to do a thorough search of the building and the island. Superintendent of the Northern Lighthouse Board
Robert Muirhead also made a visit on 29th December, writing a report on 8th January 1901.

Flannan Isles Lighthouse Mystery Clues

An eerie lighthouse in the distance (Photo: Anna Denisova / EyeEm via Getty Images)

The east landing on the island was untouched, but on the west side, there were signs of problems. iron railings were broken, items washed away, some strewn on rocks below.

One of the most significant clues in the Flannan Isle mystery is the log book. Whilst the last written entry was from 13th December, there were notes up to 15th December detailing the time the light was extinguished as well as various mechanical readings. This, together with the prepared meal found in the kitchen, led to the conclusion that the men had been in the lighthouse up to the afternoon of 15th December.

Several anomalies were found at the scene. The clock had stopped. What’s more, whenever they left the building, two of the Eilean Mor Lighthouse keepers – Ducat and Marshall – were dressed in what they would normally wear to go to the landing. McArthur had left without his only coat, which was highly unusual.

Flannan Isle Mystery: An Accident?

Rough sea at night (Photo: Jeremy Walker via Getty Images)

“A dreadful accident has happened at Flannans.”

These were the words written in a telegram by Captain Harvey on 26th December. This sentiment was echoed by Superintendent Robert Muirhead in his report on 8th January 1901.

The belief was that, on the afternoon of 15th December, the men had been trying to secure something on the west landing when they were overcome by a large swell of water and swept away.

Rumours and Speculation

An ariel view of a lighthouse (Photo: Westend61 via Getty Images)

Some years after the disappearance of the Flannan Isles Lighthouse keepers, a logbook – purportedly the logbook written by them – was released showing strange entries between the 12th and 15th December. There was talk of a vast storm and unusual behaviour by the men and all three praying in the eye of the storm.

It is all but certain that this “logbook” was a fake. However, it shows the intense speculation and superstition associated with the Flannan Isle mystery. Indeed, everything from ghost ships to sea serpents have been mooted as possible culprits behind the disappearances.

More earthly suspicions were cast on William MacArthur, who is said to have had a history of violence. Perhaps there had been a fight on the Western landing that caused the men to fall into the sea. Or maybe a murder-suicide. However, there has never been evidence to back this up.

The Prevailing Theory

A mysterious figure looks on at night (Photo: Anton Petrus via Getty Images)

There is more evidence for the idea of a terrible accident caused when the men tried to secure something on the west landing of Eilean Mor. Apparently, workers could be fined for lost equipment and it is said that Marshall had been docked the not insignificant sum of five shillings for such a loss on a previous occasion.

Perhaps, the theory goes, Marshall and Ducat went out in the storm and were swept away. Maybe MacArthur, wondering at his missing colleagues, went in search of them and suffered a similar fate.

A Captivating Tale

The mystery remains today (Photo: Mohd Hafiez Mohd Razali / EyeEm)

It is unlikely that the truth behind the Flannan Isles Lighthouse mystery will ever be uncovered, or the fate of its lighthouse keepers ever truly known. Nevertheless, the tale has never lost its ability to captivate. It has inspired songs, an opera and Wilfrid Wilson Gibson’s 1912 poem:

“Though three men dwell on Flannan Isle
To keep the lamp alight,
As we steer’d under the lee, we caught
No glimmer through the night.

A passing ship at dawn had brought
The news: and quickly we set sail,
To find out what strange thing might ail
The keepers of the deep-sea light.

The winer day broke blue and bright
With glancing sun and glancing spray
While o’er the swell our boat made way,
As gallant as a gull in flight.

More recently, in 2019, the tale of the Flannan Isles Lighthouse keepers was the subject of the film The Vanishing, starring Gerard Butler and Peter Mullan.


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