Buckingham Palace, 10 Downing Street – No. 1, The Thames.

All enviable addresses and the last des-res could be yours for a cool £1.5 million.

One of Medway's most unusual properties, the 165-year old abandoned fort, which is also known as Grain Battery Tower, is up for sale again.

The 19th century military installation off the Isle of Grain was snapped up five years ago for £500,000 by an anonymous property developer.

But despite being marketed as a possible nightclub, hotel, outdoor pursuit centre or casino, nothing has been done to it and it continues to fall into disrepair.

Phrases like "genuine investment opportunity", "unique location" and "character property" may roll off the tongue of an estate agent.

If the new owner has the £1m needed to restore it to its former glory, it could be transformed into a seven-bedroom mansion with a difference.

The huge bomb-proof building, which is set over 2,300sqm of space, was built in 1855 and has 15ft-thick walls.

The Martello-style property was modified during the Second World War, but has barely been touched since.

It's original purpose was to protect Chatham and Sheerness dockyards as well as The Thames from invasion, so it was fitted with an enormous gun on the roof.

In 1912 two 4.7 Quick Firing guns were moved to the tower, then during WWII, it had a pair of six pounder QF guns installed.

A two-storey red brick barracks was also built on stilts to house 60 soldiers to man the fortress.

It was bought by builder Simon Cooper from south east London in 2004 who acquired it from the Crown Estate.

Yet over the last decade the fort has been on and off the market with nobody apparently willing to take on the project long-term.

It is currently on the books of estate agents Moxy Property Consultants and is said to have already created interest among potential buyers.

One of its drawbacks is it can be accessed only by a half-mile causeway during low tide or by boat.

At high tide, the tower is completely cut off from the mainland and is accessible only by boat or helicopter.

The building also does not have electricity or running water and is around four-and-a-half miles from the nearest train station of Swale.

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