D-Day veteran beating Ed Sheeran, Taylor Swift in the charts with World War II tribute 'Shores of Normandy'

LONDON -- D-Day veteran Jim Radford, 90, has become an unexpected chart-topping sensation in the U.K. with a veterans' tribute song that's beating Ed Sheeran, Taylor Swift and Justin Bieber in the singles chart.

Radford, who was just 15 during the D-Day landings, wrote his song, "Shores of Normandy," 50 years ago after returning to the site of D-Day on the 25th anniversary. The song's been rereleased by the Normandy Memorial Trust for this year's 75th anniversary to raise funds for a new memorial on the beaches where the invasion took place.

In an interview with ABC News in the gardens of the former St. Paul's School in London, where final plans for D-Day were finalized, Radford said that he was "overwhelmed by the response" to the song.

Radford was a galley boy serving on a tug boat during the invasion, he said. The youngest of three brothers who all served in the British Merchant Navy, Radford was able to join the war effort because tugboat companies were excepted from a Merchant Navy rule that recruits had to be at least 16 years old.

"I didn't know when I went that my first trip was going to be the invasion of Europe," he said. "The song is to remember the brave lads that didn't come back."

The experiences that informed the song are still very much alive for Radford, who recalls the D-Day landings with outstanding clarity.

"Your main concern [in the fighting] is not to let your comrades down," he told ABC News. "You're not thinking about king or country, you're not thinking about democracy. You're thinking about, 'My mates depend on me, as I depend on them.' That stayed with me. Anyone who was in Normandy, we all feel that bond to each other. And especially to all the lads who didn't come back."

Radford, now a member of an anti-war organization called Veterans for Peace, said he hopes the song will shed new light on the experiences of those who died during the second World War.

"The significance and seriousness has been forgotten," he said. "I don't think youngsters nowadays realize just how serious it was … 1 in every 4 merchant navy seamen was killed during the war."

And although Radford batted off questions about his recent fame -- "It won't last!" he said -- he is clearly delighted with the success of "Shores of Normandy."

"We want you all to download the video … and you'll help us build this memorial," he said. "The message I want to get across is that we must not let this happen again."