PORTSMOUTH, England (AP) — The British D-Day veterans who gathered Monday to kick off events marking the 80th anniversary of the landings in Northern France didn’t need a calendar to remember June 6, 1944.

The events of that day remain etched on their minds, unforgettable in their horror, inexplicable in their pain.

The mood was somber as about 40 of those who took part in the operation visited Southwick House, on the south coast of England, the Allied headquarters in the lead up to the Battle of Normandy. The event, sponsored by Britain’s Ministry of Defense, came before many of the veterans travel to France for international ceremonies commemorating D-Day.

Les Underwood, 98, a Royal Navy gunner on a merchant ship that was delivering ammunition to the beaches, kept firing to protect the vessel even as he saw soldiers drown under the weight of their equipment after leaving their landing craft.

“I’ve cried many a time … sat on my own,’’ Underwood said. “I used to get flashbacks. And in those days, there was no treatment. They just said, "Your service days are over. We don’t need you no more.’’’

But the aging veterans still find the strength to speak about their experiences, because they want future generations to remember the sacrifices of those who fought and died. With even the youngest of them now nearing their 100th birthdays, they know they are running out of time.

George Chandler, 99, served aboard a British motor torpedo boat as part of a flotilla that escorted the U.S. Army assault on Omaha and Utah beaches. The history books don’t capture the horror of the battle, he said.

“Let me assure you, what you read in those silly books that have been written about D-Day are absolute crap,” Chandler said. “It’s a load of old rubbish. I was there, how can I forget it?

“It’s a very sad memory because I watched young American Rangers get shot, slaughtered. And they were young. I was 19 at the time. These kids were younger than me.”