Swimming with dolphins is promoted as one of the few treatments that can help children with disabilities such as autism. But it should be banned because it is cruel to the animals and dangerous to patients, and there is no evidence that it actually works, a report from a leading conservation group says.

The Whale and Dolphin Conservation Society said that dolphin-assisted therapy (DAT) was “expensive and potentially harmful” and its call to end it has been endorsed by the charity Research Autism. Both say that the techniques exploit vulnerable families and captive animals and have no place in medicine.

The therapy places patients at serious risk of injury from their contact with dolphins, which are wild animals that can be aggressive or harm people inadvertently because of their strength, the society found. They have been known to bite, ram and slap swimmers, to hold them underwater and to engage in sexual activity.

The therapy also exposes people and animals to the risk of infection. Many dolphins carry bacteria that can infect human beings and some are infected with bacteria that cause brucellosis, which causes muscle pain.

DAT raises stress among captive animals and encourages the removal of dolphins from the wild: 28 dolphins have recently been exported from the Solomon Islands to Dubai, reportedly for this purpose.

All this costs the families of ill and disabled people thousands of pounds for therapeutic techniques that have never been found to be effective in proper trials.

Cathy Williamson, the author of the report, said: “Having researched this industry the only recommendation we can make is that there is a total ban on DAT. This therapy involves vulnerable people and also exploits the dolphins, which are forced to interact with people in conditions that are far from suitable for wild animals.

“We know that keeping dolphins in captivity has serious welfare implications for these animals, including a shorter life expectancy than in the wild, and we are saddened that the growing DAT industry is causing more and more animals to be subjected to a life in captivity.”

Richard Mills, of Research Autism, said: “We understand that parents will wish to do anything that might potentially help their child but we would urge people to exercise caution when considering such an undertaking.” The charity’s website gives the treatment three exclamation marks, indicating a therapy with very strong evidence of harmful effects.

Since the 1970s dozens of centres around the world have offered children and adults with a wide range of physical, psychiatric or developmental disabilities the chance to swim with, stroke and feed the marine mammals, usually in captivity but occasionally in the wild, at a typical cost of at least £1,500 for five 40-minute sessions. As there are no centres offering the therapy in Britain, and most are in the US, the cost to British patients can be much greater because of flights and accommodation.

Dozens of British children have travelled to Florida and other foreign providers for treatment, often after local fundraising campaigns. The experience is claimed to improve social interaction, speech, mood, concentration and even movement and motor skills for people with conditions ranging from Down’s syndrome to muscular dystrophy.

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