THERE are some photographs a photographer never forgets taking, however long ago it was. “You feel them in your heart,” says David O’Neill. One such picture, for the former Mail on Sunday chief photographer, was the shot he took of George Adamson, the legendary lion conservationist, in Africa in 1984.

Adamson and his wife Joy became household names following the film Born Free. By 1984, when David caught up with him at Kora in Kenya, there was something almost lion-like about Adamson himself, with his mane of hair and beard, and his far-seeing eyes.

David was on assignment to help him find some of his lions, which had gone missing. Late one evening, the pair climbed a hill behind camp.

“As the light became golden and the sun was setting I asked George to rest a moment,” says David, now a freelance who lives at Bolton Percy. “This image of him captures his amazing spirit and profoundly affected me and how I chose to approach my life in future.”

Adamson was famously killed five years later – murdered by bandits, or possibly poachers, in an ambush a few miles from his isolated camp in northern Kenya. He was 83.

There was something special about him, David says, that profoundly affected the young photographer when he met him a few years before that. “It was his dignity. He was just a selfless man, with a huge sense of right and wrong. He became my hero. He changed my life.”

During more than 30 years as a photographer – he started his career in York with John Pick’s renowned Yorkshire Press Agency in 1978 before joining the Mail on Sunday in 1982 – David has travelled the world in pursuit of great pictures and the drama and tragedy of life.

He has been run over, shot at and beaten up; he has covered wars in Iraq and Afghanistan, and the sieges of Sarajevo and Kosovo; he has hunted for the Yeti in the Himalayas with mountaineer Chris Bonnington; and has photographed children playing on the beaches of Zanzibar, the spice island off Africa’s east coast.

Time, then, for a retrospective of his work, decided the 53-year-old, who describes himself as ‘unattached’. He has selected 40 of his most memorable black-and-white photographs for an exhibition of his work that will run at Grays Court in York for a month from June 15.

The photographs reproduced in The Press today are just a few of them.

He was in Afghanistan when he took the stunning, pin-sharp photo of Taliban fighters fleeing across the Pyanji river in northern Afghanistan. It was 2002.

“I was travelling down from the mountains, trying to reach Kabul. I was by the river, and these guys came paddling across on a raft and leapt off,” he says. If it had been a few years later, by which time the Taliban was not very fond of foreign journalists, he would probably have been shot, he says. But they just carried on past without even sparing him a glance.

The photo of a young boy sleeping under a tattered blanked on a litter-strewn field was taken in November 2000, at Kukas on the Albanian/ Kosovo border. The boy was a young Albanian who was among the refugees who had streamed across the mountains to escape ethnic cleansing. Both his parents had been killed, David recalls.

What struck him most about the refugees was how they had somehow managed to hold onto their dignity. “These people had lost families, wives, husbands, children. But they kept themselves together, they held on to their dignity.”

• Living Eye, an exhibition of a quarter century of photographs by David O’Neill, runs at Grays Court, Chapter House Street, York, from June 15 until July 13. Entry free.