In 2017, British tech entrepreneur Mike Conner bought Thorne Island, a ruined 19th-century fort off the coast of Pembrokeshire in Wales, for about £500,000 after seeing a video about the property online.
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Conner → buy → property
At the time, the island had no electricity or running water and the fort had been left in a derelict condition after earlier attempts to revive it as a hotel failed.
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attempts → have → hotel
Conner, the former chief executive of software company Appsbroker, subsequently embarked on an extensive restoration of the Victorian fort, investing around £2 million in the project.
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Conner → embark → project
The result is a property with more than 8,000 square feet of accommodation, five bedrooms and enough space to sleep up to 20 guests.
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result → sleep → guests
The restored island has solar panels, battery storage, heat pumps and other infrastructure that allows it to operate independently of mainland utilities.
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it → restore → utilities
In August 2025, Conner put Thorne Island on the market for £3 million through Strutt & Parker.
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Conner → put → Strutt
The military history of Thorne Island fort off the coast of Pembrokeshire
Thorne Island sits at the entrance to Milford Haven, a strategically important waterway leading towards the former Royal Dockyard at Pembroke Dock.
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Island → sit → Dock
The fort was constructed between 1852 and 1854 as Britain expanded its coastal defences amid concerns about the growing strength of the French Navy under Emperor Napoleon III.
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Britain → construct → III
It formed part of the wider group of Victorian coastal fortifications associated with Lord Palmerston's defence programme.
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It → form → programme
The fort was designed to accommodate a garrison of about 100 men and featured a seaward-facing artillery battery.
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fort → design → battery
Its original armament included five seven-inch Armstrong guns and four 68-pounder guns, mounted in open positions behind the parapet.
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armament → include → parapet
The landward side contained the defensible barracks, while the fort's thick walls provided protection for the garrison and artillery.
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walls → contain → garrison
Thorne Island's military role eventually ended, and in 1947 the fort was converted into a hotel.
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fort → end → hotel
The property subsequently changed hands several times.
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property → change → hands
It was sold for £275,000 in 1999, and in 2001 the Von Essen hotel group acquired the island with plans for a £4 million five-star hotel and a cable car linking it with the mainland.
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group → sell → mainland
Those plans did not materialise.
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plans → materialise → ?
The island was sold again in 2011 and was put back on the market in 2016 before Conner acquired it the following year.
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Conner → sell → it
How Mike Conner restored the ruined fort into an off-grid island home
Conner's restoration involved far more than renovating the interiors.
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restoration → restore → interiors
When he bought the island, the fort lacked basic utilities and had suffered years of exposure to moisture.
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fort → buy → moisture
The isolated location also meant that construction materials and equipment had to be transported from the mainland by helicopter or boat.
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materials → mean → helicopter
Contemporary reports say hundreds of helicopter trips were required during the restoration, while builders lived on the island for several years as work progressed.
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work → say → years
The restoration included extensive work to the historic granite structure, as well as the installation of modern water, heating, sewage and electrical systems.
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restoration → include → systems
Reports have put the overall investment at around £2 million, with a substantial portion devoted to renewable-energy and infrastructure systems.
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portion → put → systems
These include solar panels, battery storage and heat pumps, while a dedicated sewage system and water-treatment infrastructure allow the island to function without conventional mainland utilities.
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island → include → utilities
Conner has described the project as a personal challenge undertaken after his career in technology.
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Conner → describe → technology
He bought the island after seeing it advertised as a derelict property and spent years turning the former military installation into a functioning private retreat.
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it → buy → retreat
The restoration retained much of the original character of the fort, including exposed masonry, vaulted ceilings and the historic layout, while incorporating modern living spaces.
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restoration → retain → spaces
What the restored Thorne Island fort offers today for £3 million
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fort → restore → million
The finished property now contains just over 8,000 square feet of accommodation spread through the restored fort.
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property → contain → fort
The current sale listing describes five bedrooms, an open-plan kitchen and snug, large reception and dining areas, a games room and a rooftop bar.
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listing → describe → bedrooms
Several rooms retain exposed traditional brickwork and vaulted ceilings, while large windows provide views across the surrounding waters.
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windows → retain → waters
The island also comes with its own private jetty and helipad, allowing access by boat or air.
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island → come → boat
A hydraulic crane is used to move supplies and equipment between boats and the island, an important feature given that Thorne has no conventional road connection to the mainland.
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Thorne → use → mainland
The property is being marketed for private residential use as well as potential commercial or hospitality purposes.
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property → market → use
Thorne Island covers about 2.5 acres and the fort is a Grade II* listed building.
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fort → cover → acres
Its location also places it within the wider Pembrokeshire coastal landscape, with the surrounding waters forming part of an area known for marine wildlife and historic shipwrecks.
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waters → place → wildlife
The island itself has therefore retained both its military heritage and its unusual position at the entrance to Milford Haven.
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island → retain → Haven
After years spent turning a derelict Victorian fort into a functioning private retreat, Conner put Thorne Island on the market in 2025 for £3 million.
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Conner → spend → million
The sale listing presents the property as a rare combination of historic architecture, private-island access and modern off-grid infrastructure, while leaving its next use open to whoever takes on the unusual Welsh property.
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whoever → present → property
The Aporia
