Follow the yellow granite road The Barclay brothers have opened up Brecqhou, their secret retreat in the Channel Islands ©Archie Brooksbank Fort Brecqhou, the private home of Sir David and Sir Frederick Barclay, on the island of Brecqhou As the MV Brecqhou Lass pulls alongside the jetty, a sign comes into view, clearly written in both English and French: "Private Island - Landing Forbidden." Scrambling up the wave-washed steps, I run straight into Aidan Monaghan, the island's deputy general manager. Not long ago, he would have been here to evict me. Today he just wants to help me out of my life jacket and into a waiting golf buggy. This is Brecqhou, a tiny speck in the English Channel, separated from its closest neighbour, Sark, by just a few hundred feet of swirling sea - yet off limits to the public for nearly 20 years. While Sark attracted thousands of holidaymakers every year for long summer breaks or day trips, its neighbour welcomed just one family - that of the owners, the Barclay brothers, the British businessmen whose empire includes The Telegraph, The Spectator and The Ritz hotel in London. The publicity-shy brothers, whose wealth is estimated by The Sunday Times Rich List at £2,250m, bought Brecqhou in 1993 and built a £60m, 92-room, mock-gothic castle to be their home, a retreat where absolute privacy could be guaranteed. Now, in a dramatic about-turn, the Barclays have decided to invite the public to visit, albeit only on organised half-day tours. As Monaghan drives me up the winding track from the jetty, Brecqhou at first appears similar to Sark. Stubbly grass pushes through stony ground, bright yellow flowers erupt from gorse bushes and all around the wind whittles exposed rocks into free-form sculptures. But unlike Sark there are no beaches, sheep or cattle, and once you reach the central plateau at the top of the cliffs and venture past the wall dividing wild ground from gardens, you enter a very different environment. Under the ownership of the Barclays, all available space on what could otherwise be a bleak, windswept place has been transformed into an 18-acre secret garden. "There were no trees or grass in the early 1990s," says Monaghan. There wasn't even a jetty or a harbour to bring anything ashore, so the first materials had to be delivered by Chinook helicopter. Once the jetty was built, his team brought in around 90,000 tonnes of building materials. We started building the house in 1994 and the family were able to sit down for Christmas dinner there in 1996. The boat to Brecqhou Work on the garden began in 1997. Fences were installed as wind breaks before more than 184,000 trees, shrubs and flowers were planted. The gardens now include a vineyard with 4,000 vines, a Giverny-style lake complete with red Japanese bridges, waterfalls, lush lawns and countless zones of plants, all linked by a pale yellow granite road. It is all so well manicured you might think you were in Disneyland until you catch the view towards Herm and Guernsey and remember you are on a tiny island in the English Channel. Simple curiosity will draw many to Brecqhou but visiting such a pristine series of private gardens is a rare pleasure, certainly worth the 15-minute boat ride. Before I leave I stop for tea and biscuits at the Dog and Duck, the wood-panelled bar for the 16 staff who live permanently on Brecqhou (there are no other residents). Even now, tourists are not allowed to enter the main house, Fort Brecqhou, a turreted rectangle of Spanish granite resembling a seaside Balmoral. Even photos of it are forbidden and tourists are watched by CCTV when in its vicinity. However, pictures of the gardens and chapel are allowed. Built in 2003, the non-denominational chapel, with its Venetian glass mosaics and blue and gold ceiling, was designed by Sir David Barclay and is the closest you get to seeing the brothers" taste in interiors. Pews are made from an oak staircase taken from the manor house that once stood on the site of Fort Brecqhou. But why the sudden desire to invite guests into their private sanctuary? The official line is that the Barclays simply want to share the fruits of their labour. After running a small number of trial visits over the past three years, they decided the time was right to officially launch the tours and begin to publicise them. The first group of holidaymakers landed on Brecqhou on April 5, and the tours will now run three times a week, with a maximum of 40 on each. "Ten years ago we didn't have anything to show on the island," says Monaghan. Now we have something to show we are happy for people to come and see it. Others might see the opening of Brecqhou as an attempt at rapprochement with those among Sark's 600-strong population who resent the Barclays" interference. Like the other Channel Islands, Sark and Brecqhou are crown dependencies but are not part of the UK. Sark was Europe's last feudal state until 2008, when democracy arrived on the island after the Barclays mounted a legal challenge to ancient laws such as primogeniture and the inheritance of seats in the Chief Pleas, the local parliament. While many supported the reforms, others felt the brothers were trying to exert excessive control over the island and not everyone shares their vision for its future. Since 2007 the brothers have invested £30m on Sark, and have ambitious plans to develop tourism on the island, turning it into a more upmarket retreat, rather than a traditional "bucket and spade" destination. Key is the purchase and renovation of four of the island's six hotels, now collectively marketed as Sark Island Hotels. "The future of Sark is in tourism, and by developing Sark Island Hotels into places people want to stay all year round, we can help the economy of the whole island," says Kevin Delaney, managing director of Sark Estate Management, the company that administers the Barclays" properties on the island. The most recently completed is the Dixcart Bay - the island's oldest hotel, having been trading since the mid-19th century - which is due to reopen on May 25 after a closure of more than two years. "It would have been much easier to pull it down and rebuild," says Peter Tonks, the manager. But it is such a magnificent building with so much history we could never imagine that. With marble bathrooms, bespoke oak furniture and a smart raspberry and lime colour scheme, the accommodation has moved on a long way since Victor Hugo stayed there in the 1860s. ©Chris George Cyclists on the nearby island of Sark, where the brothers have also invested in tourism and vineyards Gastronomy is also central to the Barclays" plans for tourism on Sark. Thanks to the policy of using locally produced, reared or caught food, all four hotels have three-star ratings from the Sustainable Restaurant Association and are in a position to showcase the best of Sark produce. Typical dishes at La Moinerie include thick fillets of Sark sea bass pan-fried with buttered spinach, or a salad of local lettuce, poached lobster and crab. Prices are lower than those on the mainland because the hotels buy directly from local fishermen. At the Aval du Creux the menu is equally localistic, although more formal. Delights include hand-dived scallops, zingy berry sorbets and tender slices of island-reared beef served with garden carrots and courgettes. By using a mixture of organic kitchen gardens, hot houses and polytunnels, the island can grow almost everything it needs for seasonal dining, allowing food to be fresher than imported items. Another part of the Barclays" plans is the development of the island as a high-quality wine producer. Already 100,000 vines have been planted, under the stewardship of Bordeaux wine consultant Alain Raynaud, and there is even talk of creating a sparkling rival to champagne. Nevertheless, much of Sark's appeal revolves around attractions that date from long before the Barclays" time. There are glorious beaches, glades of wild flowers, pretty cottages and an absence of street lights (creating prefect conditions for star-gazing) and cars. Bicycles or horse-drawn carts are the only transport. Stay at one of the Barclays" hotels, though, and, as well as fine food and luxurious furnishings, you have one key advantage - complimentary trips to Brecqhou. Tours are open toothers but must be arranged via the Barclays" hotels and at a cost of £38 per head. Rather than seeing the opening of Brecqhou as an olive branch, will the brothers" fiercest critics therefore resent it as another means of promoting their growing interests on Sark? "We are all working towards making Sark better known as a destination," says Peter Cunneen, marketing manager for Sark Island Hotels. And part of the attraction of coming to Sark is Brecqhou. Julia Hunt was a guest of Sark Island Hotels (www.sarkislandhotels.com). Brecqhou tours are free for those staying two nights in any of the group's hotels