A ROYAL Navy veteran told London's High Court on Friday how witnessing two nuclear bomb tests more than 50 years ago left him with life–threatening cancer.

Arthur Hart observed the two tests - codenamed Mosaic One and Two – off the Pacific island of Monte Bello in May and June 1957 while serving on HMS Diana as an 18–year–old engineering apprentice.

The 71–year–old, of Greenbank Road in Stockton Heath, was stationed on the destroyer's upper deck during the blasts. His role was to hose down fellow crewmen to prevent contamination in the boiler room.

He saw a lightning–like flash from the sky when the bomb exploded and then saw the mushroom cloud in the aftermath of the blast.

Mr Hart, who was diagnosed with bowel cancer six years ago, was serving in the Royal Navy as part of his national service.

He is among more than 1,000 servicemen now suing the Ministry of Defence for hundreds of millions pounds in compensation over alleged negligent exposure to radiation during atomic and nuclear tests in the 1950's.

The claimants say they or their loved ones suffered illnesses including cancers, skin defects and fertility problems due to exposure to ionising radiation during the South Pacific tests.

But MoD lawyers maintain that they have left it too late to sue and that the claims have "no reasonable prospects of success".

Mr Hart said the ship's company was only told a few days before the exercise that HMS Diana's role would be to steam through the nuclear fall–out.

The purpose, he understood, was to assess how the ship and crew would react in the face of nuclear blasts to evaluate military capacity "in the event of a nuclear war".

He said he had no recollection of any safety or health warning being issued, although he was provided with "anti–flash clothing" to guard against the heat and light given off by the blast.

No mask or respirator was supplied and none of the crew had any concerns about any dangers to their health.

But within three years of the tests he began to develop unsightly skin lesions.

He was diagnosed with bowel cancer in 2002, undergoing surgery and intensive chemotherapy, which, although successful, was ‘painful’ and ‘emotionally harrowing’.

Mr Hart is one of 10 lead claimants spearheading the case. The hearing, before top judge, Mr Justice Foskett, continues.