Horse Sand Fort in the Solent, Portsmouth, sold for £715k

But now one of the three Solent Forts off Southsea beach looks destined to become a luxury leisure facility.

Horse Sand Fort, which is undeveloped, has been sold to a private UK purchaser, for £715,000 through Colliers.

They plan to use it for leisure, although specific plans have not yet been unveiled.

General view of Horse Sands fort, which is part of Solent Forts and is up for sale with Clive Emson Land and Property Auctioneers. It is one of three of the Solent forts that are former 'Palmerston Forts' built in the 19th century. PA Photo. Picture

The three former sea defences had been owned by entrepreneur Mike Clare who decided to sell them in 2019.

The entrepreneur is keen to sell the two remaining, and working with Colliers has now set a deadline for bids for No Man’s Fort.

Paul Barrasford from Colliers’ Hotel Agency said: “Following our recent sale of Horse Sand Fort, Mr Clare is keen to progress on No Man’s Fort and has reduced the asking price to £3.6m and set a deadline for offers to come forward.

“There are not many people who can say that they own a fort, this site could be an amazing addition to a property portfolio, whether it is used as a hotel as it is now, a holiday residence or converted into a different use.

“For a creative investor it could be many uses such as a data centre, specialist athletic training venue, a filming location, or even a headquarters for a fast-growing start-up.

"Its remote location offers the ultimate privacy and security."

A view of the atrium inside No Man's fort, which is part of Solent Forts and is up for sale with Colliers along with Spitbank Fort. The two forts are former 'Palmerston Forts' built in the 19th century and today are both luxury hotels. PA Photo.

The 99,000 sq ft island is currently developed as a 23-bedroom luxury island retreat which was refurbished in 2015, with spa, restaurants, helipad, and events space.

More recently additional landing stages and new generators have been installed, as well as the fort’s own pub.

Previously No Man’s Fort was marketed for £4.25million, but now the asking price has been dropped to £3.6million and deadline of Friday November 26 set for bids.

General view of the lighthouse on No Man's fort, which is part of Solent Forts and is up for sale with Colliers along with Spitbank Fort. The two forts are former 'Palmerston Forts' built in the 19th century and today are both luxury hotels. PA Photo.

The third Spitbank Fort is also available for purchase under separate negotiation.

All three forts are built with granite walls and armour plating, and can only be reached by helicopter or boat.

They were first commissioned by British Prime Minister, Lord Palmerston, to repel the threat of a French invasion in 1859, but were never used for their main purpose after taking too long to complete.

It is believed they took around 15 years from start to finish.