Spitbank Fort, Portsmouth

LOCATION: Spitbank Fort is near Portsmouth – but not in the same way that any other hotel near Portsmouth is near Portsmouth.

LOCATION: Spitbank Fort is near Portsmouth – but not in the same way that any other hotel near Portsmouth is near Portsmouth. This country house hotel has a major difference – it’s off-shore, sitting in the middle of the Solent. Accessed by luxury launch, you’re buzzed across the waves after being first fortified with a tot of rum in Spitbank’s dedicated departure lounge at Royal Clarence Marina in Gosport.

FIRST IMPRESSIONS: The round mass of the fort appears on the horizon like some sort of alien spacecraft – a floating saucer, if you will. Except it’s not floating. It’s built into the ocean floor – a 162ft diameter, man-made island of concrete, iron and granite, rising out of the swells of the Solent. Built as a sea defence in 1870, it’s now a deluxe, three-storey boutique hotel with a rooftop hot tub and a Laurent Perrier champagne bar. The conversion was undertaken with the support of English Heritage, so it’s sensitively done, preserving historic features including some pretty impressive canons with hefty 850lb shells.

THE FACTS: Functioning as a boutique hotel or for private hire, the fort sleeps a maximum of 18. Its huge, wedge-shaped guest rooms are named after military commanders. I’m in Vice Admiral Drake, where the heritage elements – porthole, antique globe, chairs that could have come straight from an Austen novel – are set off by the contemporary comforts of a sleek slate bathroom and marshmallow-soft bed. Across the curving corridor from each room is a ‘snug’, a sort of open brick cave which leather armchairs, low lighting and a selection of erudite books render perfect for a mid-afternoon snooze.The restaurant is in the former officer’s mess, all dark wood and leather, and next door, under the same curving brick vaults, there’s a champagne bar and lounge area kitted out with military and marine memorabilia. Food is exquisite, and served with such regularity that sinking the transfer launch on the way home feels like a feasible danger.

A GOOD BASE FOR: James Bond’s stag do. If you don’t know James, it would work just as well for a special birthday. There’s really no need to leave. The lower floor houses The Recreation Rooms, a museum-come-adult playpen, with a wine cellar, a DVD room, bar billiards, a pinball machine and a poker table. You can fish in a desultory fashion off the side of the fort or head out in the boat for something a little more serious.

WOW: The fort’s sleek, modern rooftop. During the day, we sat in the circular hot tub and sipped champagne. At night, we sat around the sunken fire pit wrapped in blankets and sipped rum. When the clouds were uncooperative, we sat in the Crow’s Nest, the glass-walled bar crowned with a jaunty red and white lighthouse, and sipped whatever we fancied from the well-stocked bar.

HOW MUCH: From £??? per person per night, or from £???? exclusive hire, sleeping up to 18 on a full-board basis.