Thorne Island
A small Welsh islet in Milford Haven dominated by a nineteenth-century Palmerston coastal fort.
Last updated August 26, 2026
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Overview
Thorne Island is a rocky islet in Milford Haven, Pembrokeshire, Wales, and forms part of the community of Angle. Covering approximately two acres, it occupies a strategically important position near the entrance to the Milford Haven waterway and the approach to the former Royal Dockyard at Pembroke Dock. The island is best known for its fort, a mid-nineteenth-century coastal defence work constructed during a period of heightened British concern about the expansion of the French Navy and the strategic ambitions of Napoleon III. The island had been considered for fortification as early as 1817, although that proposal was not implemented. Construction of the existing fort began after 1852, with the date 1854 carved above the entrance. The resulting irregular polygonal fort included a seaward battery designed for five rifled breech-loading seven-inch Armstrong guns and four 68-pounder guns. These weapons were mounted en barbette, allowing them to fire over the parapet. The landward side incorporated defensible accommodation and a loopholed parapet overlooking the entrance. The fort was one element of a broader defensive system developed around Milford Haven and Pembroke Dock. A Royal Commission report in 1860 judged that the existing batteries at Thorne Island, Dale Fort and West Blockhouse Fort could deny an enemy use of the anchorage but would not reliably stop fast warships from entering the waterway. The assessment contributed to wider reinforcement of the harbour entrance, eventually associated with a network of twelve forts and batteries, including Fort Hubberstone, Popton Fort and Stack Rock Fort. After its military use, Thorne Island entered a more unusual commercial and tourism history. In 1947 the fort was converted into a hotel and later marketed for private accommodation, weddings, parties and other events. Its architectural and military significance was recognised when the fort became a Grade II* listed building in 1996. The designation described it as a well-preserved component of the Palmerston defences of Milford Haven. The property changed hands several times. It was sold in 1999 for £275,000, and in 2001 the Von Essen hotel group owned the island and proposed a substantial redevelopment, including a five-star hotel and a cable-car connection to the mainland. The proposed works did not take place. The island was sold again in November 2011, reportedly for considerably less than an asking guide price of £750,000, and was placed on the market again in 2016 with a guide price of £550,000. Mike Conner, described in the source material as a software entrepreneur, acquired it in May 2017. Following approximately five years of restoration, the former hotel was reported in August 2025 to have been made habitable, with running water and accommodation configured for forty bedrooms, four en-suite bathrooms and a nightclub; the property was then marketed for £3 million. Thorne Island is also associated with maritime casualties. More than twelve diveable wrecks are identified in the surrounding waters, including the Loch Shiel, a sailing ship built in 1878 that struck rocks near the island and sank in 1894. All thirty-three people aboard were rescued, and two Angle lifeboat crew members together with the lifeboat's honorary secretary received RNLI silver medals. The wreck carried a mixed cargo that reportedly included gunpowder, beer and a large quantity of Scotch whisky. Salvage attempts and later diving activity have given the wreck a local reputation as a Welsh counterpart to the story popularly known as Whisky Galore. The island therefore has significance as a military heritage site, a former hospitality property and a location associated with maritime archaeology and shipwreck history.
History
Thorne Island is a small rocky islet at the entrance to Milford Haven in Pembrokeshire, Wales. Its location gives it strategic command over access to the haven and the former Royal Dockyard at Pembroke Dock. Although a proposal to fortify the island was made in 1817, construction did not begin at that time. British concern increased during the 1850s as the French Navy grew in strength and Napoleon III pursued an expansionist policy. The memory of the French landing and temporary occupation of Fishguard also contributed to anxiety about the vulnerability of the Welsh coast. The existing fort was built after 1852, with the date 1854 displayed above the entrance. It was laid out as an irregular polygon. Its seaward battery was designed for five rifled breech-loading seven-inch Armstrong guns and four 68-pounder guns, mounted in open barbette positions. The landward side consisted of defensible barrack accommodation with a loopholed parapet covering the entrance. The fort was intended to restrict hostile shipping and protect the approaches to Milford Haven. The 1860 Royal Commission on the Defence of the United Kingdom found that the batteries at Thorne Island, Dale Fort and West Blockhouse Fort could prevent an enemy from using the anchorage at the mouth of Milford Haven, but were insufficient to stop fast steam-powered warships from passing into the waterway. The assessment led to a broader programme of defensive construction and reinforcement around the entrance to Milford Haven and Pembroke Dock. The resulting system eventually included twelve forts and batteries, among them Fort Hubberstone, Popton Fort and Stack Rock Fort. Following its military period, Thorne Island was converted into a hotel in 1947. The property later served, or was promoted, as a distinctive venue for weddings, private parties and other events. The fort's historical value was formally recognised in 1996, when it became a Grade II* listed building as a well-preserved example of the Palmerston defences of Milford Haven. Ownership and redevelopment proposals have been changeable. The island was sold for £275,000 in 1999. By 2001 it was owned by the Von Essen hotel group, which proposed investing £4 million to reopen the hotel with a five-star status and to install a cable car linking the island with the mainland. The proposal did not proceed. The island was sold in November 2011 for less than the guide price of £750,000 and was placed back on the market in 2016 for £550,000. Mike Conner, identified in the reference material as a software entrepreneur, bought the property in May 2017. He subsequently spent around five years restoring the building to a habitable condition, including the provision of running water. In August 2025 the property was reported to have forty bedrooms, four en-suite bathrooms and a nightclub, and was offered for £3 million. The surrounding waters have a separate maritime history. Divers identify more than twelve wrecks of interest near the island. The best-known is the Loch Shiel, a sailing ship built in 1878 that ran onto rocks near Thorne Island and sank in 1894. Thirty-three passengers and crew members were rescued. Two members of the Angle lifeboat crew and the lifeboat's honorary secretary received RNLI silver medals for the rescue. The Loch Shiel was travelling from Scotland to Adelaide with a mixed cargo that included gunpowder, beer and a reported quantity of approximately sixty to several thousand cases of Glasgow whisky. Customs recovered part of the cargo, while bottles and other material remained associated with the wreck. Shortly after the sinking, two local men from the same family drowned while trying to bring a keg ashore, and another person reportedly died from alcohol poisoning. Later divers recovered bottles from the wreck; some beer was described as flat but drinkable, and individual bottles were reported to have reached high auction prices. These stories have made the wreck a notable part of local maritime folklore and diving culture.
- 2025
Restored property offered for sale
[1]The restored former hotel was reported to have forty bedrooms, four en-suite bathrooms and a nightclub, and was marketed for £3 million.
- 2017
Acquired by Mike Conner
[1]Mike Conner purchased the island in May 2017 and later undertook a multiyear restoration.
- 2011
Island resold
[1]The property changed hands in November 2011 after the proposed redevelopment had not begun.
- 2001
Five-star hotel plan announced
[1]The Von Essen hotel group proposed a £4 million reopening project, including a five-star hotel and a mainland cable-car connection.
- 1999
Property sold
[1]Thorne Island was sold for £275,000.
- 1996
Grade II* listing
[1]The fort received Grade II* listed-building status because of its significance and preservation as part of the Palmerston defences.
- 1947
Fort converted into a hotel
[1]The former military fort was adapted for hospitality use.
- 1894
Loch Shiel wreck
[1]The Loch Shiel struck rocks near the island and sank. All thirty-three people aboard were rescued, while the cargo became the subject of later salvage and local folklore.
- 1860
Defensive limitations identified
[1]The Royal Commission on the Defence of the United Kingdom concluded that the existing batteries could deny use of the anchorage but could not reliably prevent fast warships from entering Milford Haven.
- 1854
Palmerston fort constructed
[1]The existing coastal fort was built after 1852; the date 1854 is carved above its entrance.
Products and positioning
A heritage island and former fortification associated with military history, private hospitality, events and maritime archaeology.
Brand decisions
2017
Private restoration of the former hotelStrategyBackground
After acquiring the property, Mike Conner undertook restoration intended to make the historic building habitable.
Action taken
The restoration continued for approximately five years and included installing running water.
Aftermath
The property was subsequently marketed as a restored accommodation and events venue.
2001
Proposed conversion into a five-star hotelStrategyBackground
The Von Essen hotel group sought to bring the former hotel back into operation and reposition the island as an exclusive hospitality destination.
Action taken
The group proposed a £4 million redevelopment and a cable-car connection to the mainland.
Aftermath
No construction work took place and the island was later resold.
Sources1 sources
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