The secret of a successful spa is a simple fusion of ethical principles and good service, say Sonu and Eva Shivdasani, creators of Six Senses.

'We got into the spa and hotel business almost by accident," says Sonu. "Eva and I used to travel to the Maldives a lot, a place we love. We were offered the opportunity to buy an island there and develop a hotel, Soneva Fushi, and we jumped at the chance. First we worked with an operator who squandered a lot of the capital. Then we brought in our own people. Suddenly, we were the owners, managers and developers of an island in the Maldives. We opened the first spa on the islands in 1997.

"From the beginning we wanted to create an experience that reflected the core purpose of Six Senses. We want to deliver innovative and enriching experiences in a sustainable environment. We began with treatments such as Reiki, Shiatsu and Swedish massage, managed by Eva's sister, Ami. But we soon realised we needed to deliver something larger and a bit more elaborate.

"We looked around to see if there was a spa operator with the same philosophy as us - to strike a balance between mind and body, pampering and health. But we didn't really find anything. Most spas were doing a kind of "Asian garden" spa idea - lots of plants, beautiful surroundings, open air. They offered lots of pampering treatments that focused on the body, but not on the mind too. Or there were the other sort of spas, more like health clinics and often quite rigid, such as Chiva Som and Champneys."

Eva adds: "When we opened in the Maldives I wanted to be in complete control ecologically. Getting control of the management was central to that. Now we are planning to generate our own sources of power from the waves, wind and sun. We want to be totally self-sufficient and should be completely emission-free by 2010."

"Usually, the spa industry presents a big challenge to the environment in terms of water consumption and energy," says Sonu. "For example, think of how much water can be consumed with a water-based massage - an hour's treatment uses about as much water as an entire Sri Lankan village for a few days. So, in certain countries, where particular resources are scarce, we try to tailor our menus to the locality. It is also important to remember that 90 per cent of a guest's emissions for a two-week holiday comes from the flight. We are already offering offsetting to our guests but we plan to make it a compulsory charge in the future. The offsetting programmes we use are carefully chosen - simple forest planting is not really the most effective strategy; we prefer programmes that support alternative energy sources."

Eva adds: "Questions of fair trade and the environment are going to become far more important to people making decisions about where they are going on holiday. Luckily, we started this process almost 15 years ago. I am horrified when I see hotels in Thailand importing teak from Myanmar to build their spas. At Six Senses we never touch wood from the rainforests; this focus continues right down to little things such as refusing to send corporate Christmas cards. From the savings, by the way, we were able to put four kids from one of our projects through school. In the Maldives, nearly all our revenue from laundry goes to environmental charities. In essence, I believe you have to do what you can. We think ecology is one area where we can make a really positive impact."

"The Six Senses Earth Spa at the Evason Hideaway in Hua Hin, Thailand, is an interesting project because it really reflects our core purpose at Six Senses," says Sonu. "One of our big considerations at the Earth Spa was air-conditioning, which has a huge impact on the environment. We decided in Hua Hin to build a spa using earth, a readily available material, which can naturally cool the temperature by up to 15C.

"The spa was created by a charitable project based in the north of Thailand where the locals are taught to make their dwellings using traditional materials such as earth. We decided that, rather than just giving the charity a donation, we would give them the contract to build, initially, all the garden walls at the Evason Hideaway Hua Hin. After the garden walls proved successful, we asked them to build the Earth Spa which is now almost entirely naturally cooled."

Eva adds: "Another important part of our philosophy is that everyone is equal. People have different titles in our operations but nobody is higher or lower. You have your managing director or whatever, but ultimately it is just a job.

Sonu says: "The holistic approach to our spas and resorts also extends to our 'hosts', which is what we call our employees. One really important point to remember is that it is not the buildings that are delivering spa treatments; it's the individuals. We want our hosts to believe they are working for a company that is serving a purpose and doing good. To that end, part of our revenue goes to community projects. Our hosts help decide where this money is spent, coming up with ideas which can directly help their communities."

Eva says: "A sense of holistic egalitarianism runs through everything we do. We want happy staff because that usually equals happy guests. Our welfare programmes for our hosts are very important. We put a large emphasis on training them across the hotel's tasks so that everyone gets a chance to improve.

"We also want to instill a sense of ownership for our hosts so that they can say 'this is my hotel'. Without them, we are nothing. We pay for teaching, provide loans and give help to the local community and families of our hosts. In Thailand, the hosts work only a five-day week, which is unheard of in the hotel industry."

Sonu adds: "Spas are going to become more holistic. The world is slowly realising that there is more to healing than Western medicine - and Six Senses spa wants to participate in this. As humanity gets into a more and more stressed and commercially driven environment, going to the doctor and just popping a pill becomes a less sustainable option. Spas could help to lead this and at Six Senses we want to make the holistic approach accessible and less like a cultish boot camp."

Eva adds: "We believe that tourism can play a really positive role in developing countries. However, hotels and the tourist industry must be prepared to give - you can't just take. I get so worried about bad karma in this business. For example, we would never ever try to steal a member of staff from another hotel. You hear so many stories of this kind of practice. It is quite disgusting. Everyone knows that this industry can be cut-throat, but you don't have to be mean or cruel to be a success. To be honest, I don't really care about making endless profits. Having a decent company with good values is far more important. As long as we're OK, then what's the point of being obsessed with profit? I'm much more interested in expanding the company slowly and really keeping our values intact.

"When we first started out with the Six Senses management company we found it very hard to attract business," says Sonu. "But having now won several awards, we have become inundated with proposals from people who want us to manage their property or spa. Our senior management got together to discuss the benefits and challenges of this evolution. The main challenges were brand dilution, loss of values and loss of culture. We realised that if we just went all out to make money we'd eventually fail because we'd lose the unique culture that makes us special.

"It's important to remember that most of our resorts are destination-based - our guests visit primarily for the destination with some spa pampering attached. But we thought rather than just provide pampering we would also get in professionals, such as ayurvedic doctors, enabling our guests to put together treatment programmes lasting a whole week. We also brought in acupuncturists and healers and found that our guests quite liked this approach. Our guests then became more experienced in what a spa was and became more sophisticated and demanding.

"That whole evolution has been continuing. We are now building a new destination spa in Thailand between Krabi and Phuket, called the Spirit of Six Senses Spas, Erawan. It will be like a Chiva Som, but whereas they are really clinical we will be much more like a resort with private villas and pools. There will be lifestyle counsellors, colour therapists, yoga, etc and all sorts of healers available. Each guest will have two treatments a day even though we will still have a big focus on creating a relaxing, resort feeling. I think this balance will establish a new kind of product, filling a gap," says Sonu.

"Later in 2007, we will open a new Soneva resort on an island called Koh Kut in eastern Thailand," says Eva. "Soneva is our high-end, exclusive brand while Evason is more accessible. The Koh Kut project is going to be built almost entirely with bamboo. It will be gorgeous and secluded. I can't wait."

Six Senses Resorts & Spas (0151-226 1000; feature resorts in the Maldives, Thailand, Vietnam, Oman, and spas worldwide

Our top islands

"My favourite island is 15 minutes away from my summer place in Sweden," says Eva. "The best part is lying around on sun-warmed rocks at the water's edge. Last year we spent our 20th wedding anniversary there with a bottle of wine while watching the sun go down. It was very romantic." Sonu says: "We are also still very much in love with the Maldives. Those islands are difficult to beat. I love the unique combination of tropical forest with coral and sand."

Our favourite retreats

"Sweden has so few people it still feels untouched," says Eva. "I love the huge, eerie forests; they are breathtakingly beautiful. Openings in the trees reveal mountain panoramas and lakes filled with tiny islands." Sonu adds: "You can find remote locations: in the middle of Itacare, in the Bahia area of Brazil or Mussandam peninsula in Oman, where we are opening a spa, the Evason Hideaway at Ziggy Bay."