With its own helipad, rooftop bar and panoramic sea views, this restored 19th-century fort off the Welsh coast offers a rare opportunity to own a private island steeped in British military history
Words: Alex Fisher
Less than a mile off the Pembrokeshire coast in south-west Wales, Thorne Island is a property unlike almost any other property you could imagine. Its imposing stone fort was built to defend one of Britain’s strategically important harbours, but today its role is very different. Carefully restored and equipped for modern off-grid living, the island combines Victorian military architecture with luxury accommodation, sustainable energy and a remarkable degree of privacy.
The 2.49-acre island is being marketed by Strutt & Parker for offers in excess of £3 million. At its centre stands a Grade II* listed fort offering just over 8,000 sq ft of accommodation, together with a private jetty, helipad, sea moorings and extensive entertaining space. Currently a registered Hotel & Premises (VOA Business Rates) it offers potential for many uses from private lifestyle to commercial ventures.
Built for Defence
The fort was built on the island when fears about the growing strength of the French Navy prompted Britain to strengthen its coastal defences. Constructed between 1852 and 1854 as part of the wider network of fortifications associated with Lord Palmerston’s defence programme.
Nearby Milford Haven was an important deep-water harbour, with the Royal Dockyard at Pembroke Dock a key strategic asset. Protecting the waterway against a potential naval attack was therefore a significant military concern. Thorne Island was designed to accommodate a garrison of 100 men, with its substantial stone walls and gun positions intended to help defend the approaches to the harbour.
As military technology and defence priorities evolved, the fort’s original purpose faded. The island later passed into private hands and was converted for use as a hotel. It subsequently became a private property, but eventually deteriorated, leaving its historic structure in need of extensive restoration.
An Impossible Restoration?
Technology entrepreneur Mike Conner bought Thorne Island in 2017. At the time, the property was waterlogged, lacked windows and had no functioning water or electricity supply.
Restoring a building surrounded by water required an unusual approach to construction logistics. Helicopters were used to transport equipment and materials, including stone, topsoil and components for the new energy systems. Builders lived on the island in the original barracks for around four years during the works.
In addition to rebuilding internal areas and installing new floors and windows, considerable investment also went into making the fort independent of conventional mains services. Solar panels, battery storage and air-source heat pumps now form part of its infrastructure, alongside systems for collecting, treating and managing water and waste.
A Luxurious Interior
The restored fort combines its historic character with a layout suited to contemporary living. Its principal reception space brings together sitting, dining and entertaining areas, with exposed brickwork, vaulted ceilings, traditional-style sash windows and a wood-burning stove. An open-plan kitchen and adjoining snug provide more informal living space, with views towards the surrounding water.
There are five bedrooms and five bathrooms, with accommodation arranged to make the most of the building’s unusual architecture. Three of the larger double bedrooms have en-suite bathrooms, mezzanine floors and sitting areas. The property is can currently sleep up to 20 guests.
A glass-fronted office occupies a former lookout position on the western side of the fort, offering a distinctive workspace with views across the sea.
Outside, a lawned courtyard provides space for outdoor dining and gatherings. Steps lead to the upper grounds, where a rooftop bar and games room open onto a terrace with panoramic views across the water and the Pembrokeshire coastline.
Off-Grid Living with a Helipad, Private Jetty and Crane!
Access to Thorne Island is by boat, using its private jetty and helicopter. Five private sea moorings provide facilities for boats, and a 10-metre hydraulic crane helps lift supplies ashore.
The crane is an especially useful feature, making it easier to transport provisions and bulky equipment. The off-grid infrastructure includes solar photovoltaic panels supported by 100kWh of battery storage, air-source heat pumps, a generator, rainwater harvesting with 250,000 litres of storage capacity, reverse-osmosis drinking-water treatment and a sewage treatment system. Together, these installations are designed to allow the fort to operate independently of standard mains utilities.
This stretch of Pembrokeshire is known for its sandy beaches, rugged coastline and sailing, boating, fishing and watersports. For buyers looking for a private residence, a distinctive retreat or a property with potential for hospitality use, Thorne Island offers a combination of architectural heritage, seclusion and modern facilities. Thorne Island is for sale with Strutt & Parker for offers in excess of £3 million. For more information visit https://www.struttandparker.com/properties/angle
