One of the few New Zealanders to have worked on the atomic bomb has died in Wellington at the age of 93.
Robert Williams, generally known as Robin, was born in Christchurch in 1919 and educated at Christ's College and Canterbury University, where he got an MA in 1940.
As a mathematician he worked at the Applied Mathematics Laboratory of the Department of Scientific and Industrial Research.
In 1944 he was seconded to a British government team working on the atomic bomb in the United States in what was known as the Manhattan Project - a joint effort by the US and Britain to build an atomic weapon to win World War II before either Germany or Japan did.
Dr Williams worked to separate nuclear fuel from natural uranium for use in the so-called Little Boy bomb dropped on Hiroshima in 1945.
In 2001, he told Radio New Zealand while he had no doubt the West had to build the bomb, dropping it was another matter.
"The question really was how do you finish the war with as few loss of lives as possible," he said.
"I think there was no possible justification for dropping the second (atomic bomb) three days later. At least the Japanese ought to have been given time to make up their minds."
Dr Williams's daughter Bridget says he had a great commitment to improving life and wanted to contribute to New Zealand and the wider world.
She says she remembers him as having an energetic, curious and adventurous mind.
Dr Williams was awarded a CBE in 1973 and in 1975 became the chair of the State Services Commission.
He was Vice Chancellor at the University of Otago from 1967 to 1972 and Vice Chancellor of the Australian National University in Canberra from 1973 to 1975.
He married Mary Thorpe in 1944 and the couple had three children.
His funeral will be held at Old St Paul's in Wellington on Thursday.