Privacy, stunning river views and the enviable address No. 1 The Thames.

If this appeals, an abandoned fort in the middle of the Thames Estuary - known as Grain Battery Tower - could be the des res for you.

The former 19th century military installation, built off the coast of the Isle of Grain, has been on the market for the past decade.

But now it seems new estate agents are giving the gun emplacement tower, which has a price tag of £500,000, another push.

Builder Simon Cooper, from south east London, brought it from the Crown Estate 10 years ago with the intention of transforming it into his home.

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

Potential uses that have been suggested over the years include a seven-bedroom mansion, nightclub, hotel, outdoor pursuit centre, or casino.

However, it is estimated that about £1 million would have to be spent on it to make it ship-shape.

Jonathan Hacker, of River Homes waterside specialists, said: “We have only had No 1 The Thames on our books for four weeks – and completely by chance.

“Simon just happened to be doing some work at one of our offices and he popped in to say he had this place on the river."

He added: “We are more used to dealing with house boats on the Thames and we have never had anything as unique as this.

“It went online and suddenly sparked amazing interest both in the media and with potential buyers. We have six interested parties so far, and we have viewings planned.

“I think it’s its potential and so many possibilities that make it so appealing.”