Violent incidents like these handed an already-embarrassed Government the perfect excuse to evict the pirates. And with the introduction of the Offshore Offences Act of 1967 and a hasty and legally dubious re-drawing of British territorial limits, it did just that. By the end of the Sixties the pirate frequencies were silent. The forts enjoyed fleeting fame during the Seventies as a film location: Doctor Who, in Jon Pertwee incarnation, battled the Sea Devils from the towers while Noddy Holder and colleagues shot their movie Slade In Flame. And the SAS occasionally used the deserted towers to practice oil rig assaults. But since then, Maunsell's creations have stood, largely forgotten, eight miles out to sea. Until recently. In the last few years these imposing 20th Century ruins have become the inspiration for a piece of classical music (The Maunsell Forts by composer John McCabe), a cause celebre, the focus of an extraordinary arts project and even an unlikely tourist attraction. "We've taken 600 people so far this season, with another 500 booked," says insurance man-turned-sightseeing-boat-skipper Mike Albury. "One local lady has been out seven times. There is a lot of interest at the moment and we make the forts accessible." This Summer, Mike's company BayBlast has ferried 50 boatloads out for a closer look. At this rate, his new £45,000 rigid-hulled inflatable will pay for itself in two or three years. Mike throttles down the twin outboard engines and we slowly circle Redsand's looming towers. Up close, they are a sinister but strangely beautiful presence; corroded hulks of armoured steel perched on tall concrete legs. Painted on one rust-ravaged, half-inch thick wall are the words 'Property of R.Adcroft, for Redsand Development Corp'; still legible nearly four decades after they were daubed there by a young pirate radio DJ with grand designs on the fort. "It was going to be a hippies' paradise, an offshore hotel type-thing," Robin Adcroft explains over coffee in a Whitstable café. Robin hatched the surreal scheme with his friend Stephen Warwick, appropriately enough while the pair were working as sound men on the set of another, quintessentially Sixties caper: The Italian Job. With a young Canadian businessman bankrolling the project, plans were drawn up "but the Government wouldn't talk to us." Now in his fifties and a freelance broadcast engineer, Robin is a veteran of what he remembers fondly as a peaceful, 'free radio revolution'. He worked for both Radio Caroline and the Dutch Radio Nordzee. "I was a teenager in the Sixties and we heard the pirates coming from the forts and thought it was wonderful. When I was about 15 or 16 somebody invited me out to this particular fort, Redsand," he remembers, "It was an absolutely awesome sight. These forts with huge, 250ft masts on top and a successful radio station outside the jurisdiction of Britain. But I was more fascinated by the structure itself, this marvellous feat of engineering." Post-war secrecy meant facts about the forts were scarce. So Robin tracked down the original wartime project engineer, John Posford, who invited the inquisitive young hippy to his London offices. "We had a good old chat and he plied me with brandy. It was terrific. He was an elderly chap and he said: 'I'm not going to be around very much longer. I would like somebody to keep one of these forts for future heritage.'" That was in 1968. Today, Robin is leading an ambitious effort to save Redsand Fort. "I'm the catalyst but there's so much more to it than that," he says. As manager of Project Redsand, a group of enthusiasts united by a Government threat last year to demolish the sea forts, his aim is to restore Redsand Fort, the best-preserved of the two surviving army forts. The £3 million project could take five years or more to complete. But it already has the support of major civil engineering firms and English Heritage, which considers Redsand a 'nationally significant structure'. "We've got past the fantasy stage and we're into the reality stage now. But we won't have access to public funding unless there is some ownership," Adcroft explains, "Because obviously nobody's going to put money into something that nobody owns." Relations with the relevant Government agencies are positive. "They seem to be prepared to talk to us because we're upfront," says Robin, "Our approach is completely the opposite to the one we took in the Sixties; that the forts were abandoned, we didn't care who might own them, we're going to just do it anyway..." But then, handing over Redsand Fort for restoration could cost less than destroying it. Initial surveys have revealed the basic structure is remarkably sound. "It was going to cost £9 million to remove both army forts. It requires quite a feat of engineering. They'd at least save four or five million on that if we retain our one. The Department of Transport even asked if we were interested in Shivering Sands as well. I said 'Absolutely not! No way! It's difficult enough doing one!'" But the forts' inaccessible location could yet prove an obstacle to potential lottery funding. "The fact that it's isolated eight miles offshore is a bit of a problem," admits Robin, "A lot of people have asked how on earth can we justify spending public money on a structure that people can't just climb on board and enjoy." Few visitors have ventured on to the derelict forts in recent years, since they were ransacked by scrap dealers and the authorities removed dangerously corroded access ladders and walkways. But with the help of the Royal Engineers and Mowlem Marine, Project Redsand's volunteers are preparing to board once again. Just a few nautical miles East, meanwhile, Artist Stephen Turner is moving into Shivering Sands fort. With the most basic equipment and supplies and only seagulls for company, he aims to remain there, totally alone, for six weeks; the length of a WWII soldier's tour of duty. The self-imposed castaway's rusting, man-made island will be connected to the outside world only by radio and internet link, with local Kent schools following his progress by webcam. "He wants complete and utter isolation and there's probably nowhere on the planet quite like it," says Robin Adcroft, "But if he needs to get off in a hurry we'll have a helicopter on standby and various boats waiting for a call. So it will be well and truly monitored 24 hours a day. "He's a very spirited guy. It can get pretty howly out there. It's not that so much that, though, as the isolation. It can do something to your head. But there's a lot of pleasant aspects as well. The solitude and the wonderful experience of actually being in a solid structure in the middle of the sea. "And you get all these sonar effects," says the sound engineer, "You hear ships in the distance as sound travels through the sea. The fort picks it up almost like a microphone." Saving his beloved Redsand is likely to be a long, expensive operation. I ask Robin why he is so dedicated to preserving these obsolete fortifications from a long ago war. After a thoughtful pause, he replies: "I might as well do something useful in the last maybe 20 years I've got left. I don't have a family. I was never married. If I could leave a fort behind, it's some kind of legacy." Then, with a smile, he adds: "Of course, I might live to regret it..."