Shot amid the unfurling drama of the European migration crisis and described as “haunting” by one member of the competition jury, this black and white image by Australian photographer Warren Richardson has won the coveted World Press Photo of the Year award – the most prestigious prize in photography.

The image, which shows a father handing his young child under a barbed-wire border fence toward an outstretched pair of hands, beat more than 80,000 submissions in the annual competition.

Even the photographer himself admits the frame made him “gulp” the first time he saw it. Richardson, who comes from Mornington, Victoria, spent six months covering the migration crisis last year and told Guardian Australia the image was created on a tense night in August as refugees sought to pass from the village of Horgoš in Serbia to Röszke in Hungary.

“There were about 200 Syrians hiding in an apple tree farm, looking for a way to get across the border,” he said. “I stuck with them for about four hours and they were playing cat and mouse with the police, being gassed by the police with pepper spray. The police were yelling out: ‘Don’t come to Hungary illegally – if you get here we’re going to arrest you’.

“I knew what they had to do [to cross the border], so when they had to be quiet, I had to be quiet. I had to follow their code because I didn’t want to break their rules and hurt them.”

When the picture was taken, Richardson said, “it was just a constant flow of people running down the ditch, straight under the fence, straight onto the other side of this road into a corn field. It moved very quickly, so I literally had to take the lens up, keep it at a certain distance and just hope for luck to get a decent picture because it was so dark. It was a full moon that night, so the light in the picture is basically moonlight.”

The circumstances were so fraught that Richardson didn’t realise the quality of the image he had created until he was at home reviewing his work, and even then he hadn’t intended to enter the photo into the World Press Photo competition until his partner, who is also a photographer and photo editor, urged for it to be submitted.

“You know when you’re in a picture theatre and they dim the lights and all of a sudden the image comes on the screen?” he said, explaining the moment he first saw the photo. “Well, when I was at home I had all the lights off, because I work when my family’s asleep, and all of a sudden this picture comes up and it was the same thing. I just lifted the levels slightly and the image emerged from the darkness. It kind of made me gulp. It made my heart-rate pick up.”

Francis Kohn, chair of the World Press Photo general jury, said the image “had such power because of its simplicity, especially the symbolism of the barbed wire”.

“We thought it had almost everything in there to give a strong visual of what’s happening with the refugees,” he said. “I think it’s a very classical photo, and at the same time it’s timeless. It portrays a situation, but the way it’s done is classic in the greatest sense of the word.”

The photograph, which also took first prize in the Spot News category, is the first black and white winner of the main award since 2009 when Anthony Suau’s image of a police officer entering an empty property following the US housing market collapse was given the award.

Richardson learned of his triumph on the day he was due to fly back to Europe to continue his documentary work – he plans to walk from Serbia to the Arctic Circle in Norway, following the journeys of the refugees he met and meeting up with former acquaintances along the way.

“Every time I photograph a person I’m learning something,” he said, reflecting on the personal nature of his work. “We’re all teachers and we’re all students, no matter how old and how young. We’ve all got something to learn and something to give.”