At the Hale Clinic in London - where Princess Diana used to receive treatment - you can see anyone from an osteopath to a Qi Gong therapist.

Dr Dooja Purkitt, who was medically trained in India, practises Ayurvedic medicine at the clinic - an ancient Indian art which uses herbal remedies, yoga, massage and meditation.

He specialises in Marma - which stimulates pressure points - and with which he regularly treats stroke and some cancer patients.

"I was working with a gentleman and he had an infection every week," he said.

"He never believed anything - so I said 'OK, give me 15 minutes'. I did work sending messages to the mind, and after that he started working, and after that he believed - that's human nature."

Patients' belief

Much of the success of complementary medicine depends on the testament of its patients.

Sharon Alcock meets staff and patients at the clinic

The lack of proven evidence for many of the more unusual therapies is a huge sticking point between conventional doctors and the complementary medical world.

But - as a BBC Radio 5 Live survey this week proved - more and more people are happy to try for themselves.

Meera suffered dizziness for three years. A friend recommended she saw Dr Purkitt.

"I felt after the first treatment much, much better," she said.

"If I feel I will get better understanding and quicker treatment for what I need then I would probably avoid my traditional GP."

Colour therapy

Rene Garda take a different approach, and I submit myself for a check-up.

A quick douse and discovers she tells me I need some colour therapy on my right knee.

She believes different colours and musical notes have frequencies which correspond to the cells of the body, and by using them she treats emotional problems, fatigue and people who are overweight.

Rene herself admits her therapy is very unusual - she has developed it herself and has no proof that it works other than experience. She, like most practitioners, is used to the look that crosses people's faces when she tells them what she does. But she manages to earn a living from it.

"It costs between £60 and £95 according to if it's three-quarters of an hour to an hour and a half," she said.

She says that for this she will listen to people, provide emotional support, and, when she is away, she will perform long-distance healing.

"After several sessions we look to the future with a smile," she said.

Searching for proof

Proving value for money is a sensitive subject at the Hale.

Theresa Hale, the clinic's founder, teaches something called the breath connection - re-educating people who breathe too deeply.

She said alternative medicine was not as lucrative as some critics would make out.

"The people here earn a lot less than private doctors - I'd say that a lot of them are on lower salaries than GPs," she said.

And there was good reason to trust in the therapies, she said.

"There's a lot more research than people imagine, but there needs to be a lot more and the government sadly in this country gives very little money to research in complementary medicine."

Fringe therapies

John Eastman has been treating student Glen McFee for three years. Glen is one of many patients who are turning to complementary medicine because their conventional doctor can't help them.

He had ME, or chronic fatigue syndrome.

"I'm a scientist so I like proof. I like evidence. I like to see real things happen, but it was an alternative way of dealing with what I had," he said.

As a registered naturopath and nutritionist, John Eastman often works very closely with conventional doctors. He advises patients on their diet.

"I don't see any antagonism in principle between orthodox and complementary medicine," he said.

However, some doctors did, he said, and this was down to education.

The more unusual therapies are still relatively unpopular - an ICM poll for Five Live showed 1% of people were using crystal therapy, auricular therapy, treatment with magnets and Qi Gong.