Aboriginal people exposed to British atomic tests in the South Australian outback have been told by lawyers their fight for compensation is over because it is impossible to prove radiation caused their illnesses.

Seven atomic bombs were detonated at Maralinga in the 1950s and '60s on land that has since between handed back to traditional owners.

The Aboriginal Legal Rights Movement employed legal firm Hickman and Rose to pursue a class action in the British courts on behalf of Aboriginal people from the area.

The movement's director of legal services Christopher Charles says the firm is unable to mount a case because it cannot prove ionising radiation is dangerous to human health.

"Regrettably it's been made very clear that they just cannot proceed in the English courts," he said.

"Modern medical science has to date not been able to find a way to prove a causation link between ionising radiation and subsequent illness and until such time that causative link is proven and able to be proven, these cases won't be able to proceed.

"It's only people who might have been affected by radiation that are the ones who are able to make a claim but if you can't prove the link between ionising radiation and illness because medical science hasn't got to the stage where you can prove the link, then that's basically the end of the story."

Aboriginal people were planning to join the class action if the case was allowed to proceed.

"There were a range of people who'd been interviewed and for whom interests had been taken as to whether they could be assisted. There were a range of people Aboriginal from all over the state," Mr Charles said.

He says they were informed of the news in a DVD prepared by Hickman and Rose that was sent to Aboriginal communities at Ceduna and Yalata.

"Obviously they couldn't come out to Australia and address all of the people but providing a DVD they had a real face to face explanation as to what the position was," he said.

Mr Charles says Aboriginal people have been deeply disappointed by the development.

"I don't think that anyone's very happy about that. I've no doubt that they're not happy about it but it was our duty to give them the best possible information as to what the present situation was and that's why we got the DVD from the English law firm," he said.

"I don't think anyone would dispute the trauma that was caused to Aboriginal people and to non-Aboriginal people to servicemen, everybody, about the nuclear tests was a matter of grave ruction in Australian society at the time it occurred.

"It's certainly a matter that has rippled down over the years and it's caused a great deal of distress all over the place."

Last year, Britain's Supreme Court blocked an attempt by 1,000 British Maralinga veterans to seek compensation over the tests.