A UNIQUE opportunity to buy a ten-bedroom Napoleonic fortress located on an island off the Angle Peninsular has presented itself to a savvy investor.

Thorne Island, which was built in the 1850s to protect Milford Haven from seaborne attacks from the French, has gone on the market for just £550,000.

The Grade II-listed fort is situated a quarter of a mile off the mainland and was designed for a garrison of 100 men.

The historic property was used as a hotel in the 1980s and 90s and has been uninhabited for over ten years. It is now in a state of disrepair.

Ten bedrooms are contained mainly on the ground floor, centred on a large courtyard.

There are also three reception rooms, three bathrooms, a sauna, kitchen and numerous outbuildings.

Access to the property is only by boat, but one of the previous owners obtained planning permission to build a cable car, linking the island to the mainland.

After going on the market in 2011, the island was bought by businessman James Gardner, of Kent Mushrooms, for £750,000.

Mr Gardner, who collects forts, said: “I bought it on a whim a few years ago. It’s now surplus to requirements.

“It was in a reasonable condition when I bought it and it’s exactly as it was.

“My intention was to use a charter helicopter company to access the island. But it needs a helicopter with two engines and there wasn’t a charter company in Pembrokeshire with two.”

“It’s a magical place and the scale of it is mindboggling.”

A caretaker currently visits the island once a week to keep it in check.

The fortress is powered by two diesel generators that are in need of replacement, according to Mr Gardner.

Agents Knight Frank draw attention to Thorne Island’s “delightful coastal scenery”.

“It is ideally suitable as a residential property for exclusive use for holiday and weekends combined with a highly individual hotel potential,” states the brochure.

Now with much of the décor in a state of disrepair, a buyer would need to invest significantly to fully equip the property.