19th century Welsh island fort, shrouded in secrecy, up for sale
Thorne Island: A Historic Fort Turned Luxurious Private Island
Thorne Island, a 19th-century Napoleonic fort located off the coast of Pembrokeshire, Wales, has undergone a remarkable transformation from a derelict, windowless shell into a luxurious private island retreat.
Originally built between 1852 and 1854 as part of a wider plan to strengthen national defenses against a possible Napoleonic invasion, the fort was designed to house 100 men and constructed from local granite, featuring seaward-facing gun batteries. Today, it stands as a Grade II-listed historic fortress, enclosed by thick granite walls that shield five plush bedrooms, grand dining halls, and terraces sheltered from Atlantic winds.
British tech entrepreneur Mike Conner, the founder of Qodea, purchased Thorne Island in 2017 for approximately £500,000 ($670,000). After a lengthy restoration project costing over £2 million, the island was put back on the market in 2025 for £3 million.
The overhaul of Thorne Island's fort included a £300,000 investment in renewable energy and a biodigester system for wastewater, making the renovated property completely self-sufficient. Modern amenities such as underfloor heating, mezzanine bedrooms, a sea-view office, and a 10-meter hydraulic crane for lifting boats and supplies have been added to the historic structure.
Unique features of the island include a helipad, a covered rooftop bar with a games room, and a sea-view office. Originally designed to house 100 men, the restored property can today sleep up to 20 people in its five plush bedrooms. Access to the island is exclusively via boat or helicopter due to its isolated location about three nautical miles from the mainland.
Surrounding natural attractions like caves, fishing spots, rocky outcrops, and sandy beaches make Thorne Island an "adventurer’s paradise." The fort's renovation took over four years and required 350 helicopter trips.
Mike Conner, who has a degree in industrial design, embarked on the project as a personal challenge. After completing the renovation, he is now looking for a new challenge. He believes the renovated fort on Thorne Island could be a perfect venue for luxury retreats and celebrations.
Thorne Island, with its rich military history and luxurious modern features, offers a unique blend of charm and comfort on a secluded private island setting. Currently, offers in excess of £3 million are being sought for the property, as listed on the Strutt & Parker website.
The luxurious private island retreat, Thorne Island, has been transformed into an appealing venue for real-estate investing, showcasing not only its historic significance as a 19th-century fort but also its latest amenities ideal for luxury retreats and celebrations. Mike Conner, the investor behind Thorne Island's restoration, has financed the project with a substantial investment, aiming to make the property entirely self-sufficient with renewable energy sources and advanced waste management systems.
