Positioned just off the Pembrokeshire coast, by Milford Haven, lies an abandoned 19th-century fort, which has been undisturbed for nearly a century.

The Stack Rock Fort sits just 800 yards off the Milford Haven coastline and has been there since 1850.

So take a step back in time as we explore the history behind this secluded Pembrokeshire monument.

The story behind Pembrokeshire's Stack Rock Fort

The Stack Rock Fort was constructed between 1850 and 1852, before being extended later in 1870.

It was built to defend Milford Haven and the Royal Naval Dockyard at Pembroke Dock against an invasion from France under Napoleon III, according to Atlas Obscura.

Despite being developed in the early 1850s, the original idea for the fort actually dates back more than 300 years earlier to 1539.

Thomas Cromwell, who was an English lawyer, statesman and chief minister to King Henry VIII, proposed the fortification of the island in 1539 to protect the Milford Haven Waterway, "but nothing ever came of the plan", Atlas Obscura explains.

It added: "Similar proposals and surveys of the island followed in 1748 and 1817, but it wasn’t until the mid-1800s that any plan came to fruition."

Stack Rock Fort was orginally built back in 1850 to 1852.Stack Rock Fort was orginally built back in 1850 to 1852. (Image: Western Telegraph) However the fort's importance begun to dwindle and by 1895 most of the artillery inside had been removed.

"Although it did retain a key role in covering a nearby minefield," Atlas Obscura added.

It was manned by a small number of soldiers during World War I before being disarmed fully and abandoned in 1929.

In the end, the fort never really saw combat.

Stack Rock Fort goes up for sale

Stack Rock Fort was first put up for sale back in 1932 and sold for just £60, according to Atlas Obscura.

It was listed again in 2015 at an asking price of £150,000.

Atlas Obscura said: "But it proved to be a tricky place to sell.

"Considering the island location, and the lack of sewage, water, and power, it’s perhaps unsurprising that this impressive ‘colosseum at sea’ took a while to sell and resisted development plans."

Stack Rock Fort sits just 800 yards off the Milford Haven coastline.Stack Rock Fort sits just 800 yards off the Milford Haven coastline. (Image: Getty Images) I was eventually taken off the market and relisted in 2018.

Stack Rock Fort set for new lease of life

The fort was eventually purchased in 2020 by Anoniiem, a community interest company, which plans to preserve it as a "living ruin", according to the BBC.

Speaking to the broadcaster last year, the company's director Nick said: "We want to preserve it in its current state, not in its formal use, so if it can be stabilised as it is, in this amazing combination of nature and architecture, that's the goal."

So now, despite lying undisturbed for nearly a century, Pembrokeshire's Stack Rock Fort could be set for a new lease of life.

You can keep up to date with the latest Stack Rock Fort developments via the sites official Instagram page.

Inside the abandoned fort

Last year, the BBC documented photographer Steve Liddiard's visit to Stack Rock Fort.

Describing to the broadcaster what he saw while exploring the abandoned fort, Mr Liddiard said: "When you first walk through it takes your breath away.

"It's like a huge cathedral, an oval shape, completely overgrown with these sea birds circling it.

"It doesn't seem real... it looks like a film set, something from Jumanji or something like that."

RECOMMENDED READING:

He continued: "When you start walking around it you can see the actual scale of it, it's over three different levels.

"It is a complete time capsule with massive cannons inside.

"There's weeds and ivy growing all over it which sort of adds to it more than anything, I think."