The £1m pair of Victorian sea forts for sale in the waters off Britain, complete with hotel rooms, nightclub and helipad

There's something irresistible about the idea of owning your own island. Some hanker after dots on the map in mystically-beautiful locations; others see things differently, caring not for beauty and charm but instead looking for independence and an escape from the usual rules of society, as in the case of Sealand.

Without either factor at play, though, islands can still exert a powerful draw. Take the example of the two ports which have come up for sale in the Solent. There is no nature or beauty, and the city of Portsmouth is little more than a stone's throw away; yet who can look at the images on this page without wondering in awe what life on the fort (on shore? on board? it's hard to say) would be like.

Decommissioned after the war, the forts were sold off in the 1980s. Spitbank Fort was converted into a museum, and later hosted TV programmes and weekend raves.

Spitbank Fort and No Man’s Land Fort and were bought by businessman Mike Clare’s Clarenco, which has invested an estimated £8m on restoring the properties. They came up for sale a few years ago at around £4m each; now, they're for up for auction through Savills, with a bargain guide price of £1 million each.

'Throughout my career as an auctioneer I’ve seen several sea forts hit the market that have achieved impressive prices as buyers have sought to pursue these trophy assets,' says Robin Howeson, head of Savills Auctions.

'Having been carefully restored by the current owners, No Man’s and Spitbank Fort represent exceptional market value, each guided at £1 million. Both offer an opportunity like no other; a waterfront location, up to 99,000 sqft of space and a chance to champion the heritage and legacy of these iconic maritime structures.'

This type of fort has a long history. In the early 16th century, Henry VIII built an extensive set of coastal defences at either end of the Solent, part of his network of Device Forts that effectively controlled access to east and west.

In the late 1850s, a perceived threat of invasion by France led to the commissioning of a fresh series of forts in the Solent by the Prime Minister, Lord Palmerston. The massive, armour-plated structures took 15 years to build, by which time the French threat had receded and they were no longer required.

During the Second World War, the forts were used to defend the Portsmouth dockyards. Life on site was grim; those serving were deliberately chosen for their inability to swim, to avoid any attempt to escape.

That's far from the case these days. The mix of quirky boutique hotel with a nautical theme is oddly charming, particularly when you throw in some of the original Victorian details which remain to this day.

Clearly as it stands these properties are business opportunities rather than homes for sale, yet we see no reason why Spitbank in particular couldn't work as a private home. Especially for those looking for somewhere from which they can hop in the helicopter to work.

Savills will auction Spitbank Fort and No Man's Fort for a guide price of £1 million each on June 18. Follow the links to each for more details and pictures.

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