Hundreds of former servicemen involved in British nuclear weapons tests in New Zealand, Fiji and Britain in the 1950s, have begun their legal battle for compensation.
Some of the veterans arrived at the London High Court wearing their campaign medals and carrying their national flags.
The veterans say they suffered illnesses, including cancers, skin defects and fertility problems, because they were exposed to radioactive fallout.
Their lawyer told the judge there was new evidence to prove this.
Outside the court the veterans recalled what they were ordered to do in the 1950s.
"Sit down, turn your back to the bomb, and then they began to countdown, and then the bomb went off and then after a couple of seconds you were told to turn around and then look at it. You had no protection, none at all, a pair of shorts and a pair of boots and a hat, and the back of my head and the top of my head was completely burnt, I had crust on my scalp for about two to three years."
Veterans speaking outside the High Court in London
Some of the veterans have died waiting for the case to be heard.