Alcatraz on the Solent at Spitbank Fort

‘Enjoy Alcatraz!’ teased a friend as I set sail for a journey into the unknown.

A forbidding, dark grey silhouette of a circular fort loomed up from the sea as we bounced over the   waves in a rubber inflatable boat.

Just 1.2 nautical miles from Portsmouth’s Gunwharf Quays into the Solent we disembarked and climbed a narrow metal stairway for our 24 hour ‘sentence’ on Spitbank Fort.

Abandon hope all who enter here.  All hope of normality: the hustle and bustle of rush hour commuting, motorway snarl-ups, snatched snacks on desktops, early wake-up calls.

Swap for sumptuous dining, Champagne and cocktails, stunning sunsets and 360 degree sea views, sun terrace hot tub and rum tasting, relaxing sauna, chocolate and marshmallows around a firepit before retiring to luxurious spacious bedrooms, with soaring vaulted ceilings and steel armour, once used as troop dormitories.

The hammock hooks are still bolted to the ceilings of these military fortifications, menacing-looking buildings that once bristled with 35-ton cannon to repel Napoleon III.

They are known as Napoleonic forts or Palmerston’s Follies after the British prime minister who ordered their construction in case of invasion in the 1870s. None came, but they were used as barracks in World War One, and against enemy aircraft and submarines in World War Two.

There are three such forts in the Solent, two transformed into luxury accommodation.

Ta-dah!  And we’re on one of them, thanks to a dream dreamt by entrepreneur Mike Clare who sold his Dreams bed empire for £22m., bought Spitbank Fort and the three-times larger No Man’s Fort from the Ministry of Defence who saw no more military use for them. Clare describes his eccentric purchase as being ‘like a very expensive mistress.’

He spent over £3m. refurbishing Spitbank Fort.  His signature touches of kitsch and patriotism include a Union Flag draped on an upright piano, Winston Churchill poster, old telescopes, compasses and gas mask dotted around the Bolt Hole, Pump Room, Officers’ Mess, Crow’s Nest and Victory Bar _ plus wooden chests stuffed with Tornado jet shells.

Like Stonehenge, the fort is an English Heritage scheduled Ancient Monument, so no alterations may beautify the squinting slit-eyed windows or coarse concrete outer walls.

But our eight bedrooms, many named after admirals, and en-suite bathrooms, were stylish and blissfully comfortable.  Health  and Safety dictates that nobody with mobility issues may stay, nor under-18s.  One man in our group survived a tumble into the firepit, but that could have been the booze.

We enjoyed tip-top hospitality (canapés and bubbly, delicious buffet lunch and three course dinner culminating in irresistible chocolate fondant) with a tour of the Fort by manager Kyle Allen, who combines his skills as an historian and sommelier – arming me with a sword to swipe the cork from a bottle of Champagne like a swash-buckling pirate.

He beguiled us with tales of ghosts (just the one _ Sgt. Harry Attrill, killed in a disastrous gun firing exercise in 1910 _ and three of us heard things that went bump in the night); of daily half pints of 100% proof Gunpowder rum tots dispensed to the 156 soldiers to ease the hardship of nine month stretches, sharing eight loos; boasted of how the fort was self-sufficient with Artesian well, natural air conditioning and two generators; and showed where we could fish from a porthole.

As I woke to the faints sounds of a clanging buoy and lapping sea,  waves reflected on my ceiling, I  decided against catching my own mackerel breakfast.  Instead I headed to the Mess for a leisurely meal of fruit pancake stack with Greek yoghurt while others tucked into Eggs Benedict and smoked salmon omelette.

The late April weather gods were kind.  Sunshine, blue skies, calm seas and a clear view of the headland from which Nelson sailed for Trafalgar on HMS Victory.  The more modern version of naval warfare is moored at Portsmouth.  The new aircraft carrier HMS Queen Elizabeth, where fighter jets announce their presence with a deafening roar.

Equally deafening is the wail of Spitbank’s foghorn,  sounded to alert guests to mealtimes.

But now Kyle hand-cranked it to warn me of the imminent departure of our boat.  The skipper and all the passengers were waiting onboard.  Oh well, you can’t blame me for trying to extend a spell of splendid isolation on my quirky boutique Alcatraz.

• Spitbank Fort prices start from £350 per person based on 16 people sharing, includes sea transport, dinner and bed and breakfast.

• A five-hour Sunday lunchtime trip with Champagne, canapés, four-course meal and Fort tour: £125 per person. To book, please visit: www.solentforts.com