A parliamentary inquiry has begun into British nuclear tests in the South Pacific in the 1950s, which veterans say led to genetic defects.
Christmas Island - the area was used for nuclear testing
Veterans claim they were not given proper protection during the Christmas Island testing programme and their families have become ill as a result.
The inquiry will hear from scientists on the impact of the radiation and from the veterans themselves.
About 700 veterans are currently suing the UK government for compensation.
A Ministry of Defence spokeswoman said previous independent reports have concluded there is no evidence to back up the veterans' claims.
"The UK government recognises its obligations to veterans of the UK nuclear tests," she said.
"In particular, they have since 1983 commissioned three reports from the independent National Radiological Protection Board (NRPB) on possible adverse health effects of participation in these tests."
She added the MoD would consider the inquiry's report after it is submitted to parliament.
The nuclear devices were tested on Christmas Island, in the Pacific Ocean, in the 1950s.
Of the 700 veterans in the middle of legal proceedings, 400 are from the UK and 300 are Commonwealth colleagues from New Zealand and Fiji.
They claim there is a higher incidence of cancer, deformities and skin problems among the group and their families as a result.
Archie Ross was an instrument fitter with RAF Transport Command when he witnessed one of the bombs.
He told BBC Radio Five Live: "When the actual bomb went off, you didn't hear any noise. It was just a great white flash.
"You got your eyes covered with your hands, and the whole of the inside of your body lit up to the point where even through your hands and your eyelids, you could see the structure of your bones inside your hands.
Servicemen claim they were not given adequate protection
"At the same time, a tremendous heat built up, to the point where you thought, I can't take this, and just about that point it eased and then cooled down again."
Conservative MP John Baron and Labour MP Dr Ian Gibson will chair the two-day inquiry.
"The aim is to throw light on the issue," said Mr Baron. "There has been some strong scientific evidence published recently which suggests that the veterans have a case.
"We're going to call upon that scientific evidence to come and talk to us. We're also going to talk to the veterans. We did invite the MoD, but they refused to turn-up."
The MoD spokeswoman added that it was not appropriate for them to be involved in the inquiry due to the legal proceedings.