It was a great day. It was a terrible day. So, as the dwindling few who bore witness to the monumental feat of endeavour and ingenuity of D-day returned to Normandy’s beaches, emotions were conflicted. Street parties, flypasts, swing bands and sing-a-longs contrasted with solemn ceremonies where the celebratory was vastly outweighed by reminders of the scale of human sacrifice.

On the seafront at Arromanches, overlooking Gold beach where 75 years ago a blue-grey armada had filled the horizon as far as the eye could see, a lone piper marked H-hour. It was the moment at 7.26am when the first British soldier landed on Gold beach exactly 75 years ago.

Quick guide What happened on D-day? Show Hide What was D-day? D-day was an invasion of France by allied forces. It was codenamed Operation Neptune, and it aimed to push Nazi Germany out of occupied France. Five beaches in Normandy, codenamed Omaha, Utah, Juno, Sword and Gold, were the main targets for landing a large number of troops by sea. At 10pm on 5 June 1944, troops began departing from British shores to head across the Channel. Five assault groups set sail under darkness in an armada of about 7,000 vessels. Just after midnight on 6 June, aerial bombardment of enemy positions on the Normandy coast began. Special operations troops were also parachuted into France. US troops landed on Omaha and Utah beaches at about 6:30am. About an hour later Canadian forces landed at Juno, and British troops landed at Gold and Sword. Soldiers had to get off their boats, wade through the water, and seize control of the beach, all the while under heavy and sustained fire from German defensive positions. How was the plan kept secret? Despite involving a large number of troops, keeping D-day secret was vital to the success of the operation. A disinformation campaign had led the Germans to believe that Operation Fortitude was the main plan for the allies to invade the continent, via a two-pronged attack involving Norway and Calais. Even once the D-day landings had begun, German commanders were convinced they were just a diversionary tactic before the real invasion. Why is it called D-day? The D in D-day actually has no particular significance to Operation Neptune. It was common practice in the military to make plans that used the term, where the D stands for the day when operations commenced. Military planners also set H-hour, the time at which a plan was to begin. What happened next? By the end of the day, the allies had disembarked more than 135,000 men and 10,000 vehicles on to the beaches, and established bridgeheads of varying depths along the Normandy coastline. This came at the cost of 4,400 allied troops being killed, with thousands more injured or missing. There were also heavy casualties among German troops and French civilians. By 19 August, the allied forces had pushed down far enough to begin the battle to liberate Paris. German troops surrendered the French capital on 25 August 1944, two and a half months after D-day. Martin Belam

The lone piper Maj Macey-Lille, of 19th Regiment Royal Artillery (the Scottish Gunners), stood atop the decaying vestige of the Mulberry harbour still embedded in the sand, to play Highland Laddie as crowds gathered.

For veterans who had returned to Normandy, seeing the beaches and the quiet villages, now household names, that they fought their way through in France, is still overwhelming. Memories were of running for the dunes, bullets bouncing, shells screaming, beaches vibrating as the allied naval guns pounded German targets to provide cover for those going in.

The cemeteries are particularly emotional. “You think to yourself, all them lying there, why aren’t I one of them? Because I were with them,” says Ray Mellors, 94, from Nottingham, who as an 18-year-old with the South Staffordshire Regiment, had waded through the sea, “in the dark and wet”, towards Sword beach shortly after D-day.

Facebook Twitter Pinterest Ray Mellors, 94. Photograph: Handout

“It’s haunted me for the rest of my life. I sit here now, and I think to myself ‘I shouldn’t be here, really. I should be under the ground where the others are’.”

When his battalion was decimated, he was part of the reserves, waiting to be placed with others to replace men they had lost. He first joined the Welch Regiment, then the Black Watch, moving through France, Belgium, the Netherlands and finally, Germany. “And, I was always thinking to myself ‘my time is going to come, I know it is’. But it didn’t.”

“There was a lot going on,” says John Eden, 94, from Silverdale, Morecambe Bay, who as a 19-year-old private in the 12th (Airborne) Battalion of the Devonshire Regiment landed the day after D-day. “This brings back feelings you don’t really want to feel.”

He says: “Don’t forget, I was a terrified little lad.”

He could not explain why he had been drawn back. “What can you say? I had four years in the army, and this was part of it, an experience that you can’t comprehend, can you? You can’t imagine how you did it”. At Ranville war cemetery, he planned to visit “two particular graves” for fallen comrades.

Away from the cemeteries, there is a carnival atmosphere on Normandy’s streets during the 75th commemorations. Many, still find it unbelievable that local people will come up, shake their hand, and say thank you.

Revisiting the small villages, Douglas Russell, 97, who lives in Morecambe, was surprised at the warm welcome. “All the people that have turned up, people shaking my hand. It’s nice. But I’m not a hero, just an ordinary chap.”

Facebook Twitter Pinterest Douglas Russell, 97. Photograph: Handout

This is the first time he has returned since landing on Sword beach, with the 43rd Wessex infantry division two days after D-day. “Seeing all the crowds has amazed me. I am glad I came. At my time of life it’s the only chance I’ll get, isn’t it?” He went all the way to Berlin. His job was to treat the water from rivers and streams to ensure that his men had safe drinking water.

James Anderson, 97, a signalman, was seconded to the Norwegian destroyer Glaisdale, which on D-day escorted the Canadians to Juno beach, firing on the German defences to soften them before the troops ran for the beach, then closing in to provide cover. “We were hitting machine-gun posts. “And, as the firing destroyed a house, the house would fall on the machine gunner and give them more protection, so we had to go really close in and get rid of them,” he says.

Macron to Trump at D-day ceremony: fulfil the promise of Normandy Read more

He watched those on the landing crafts struggle through the waves under fire to reach the shore. “All the landing craft were flat bottomed, and I felt very sorry for the men because most of them were seasick. Then they had to go onshore against the enemy. Not very good.”

He spent the rest of June 1944 protecting the beach, until his ship hit a mine, and he was injured. They were towed back to the UK where he was hospitalised for two weeks.

“I know I am the only one left from my ship, now,” he says.

This was the second time he had returned to Normandy. He had never wanted to come back before. “It’s unfortunately part of your life, and when the war finished, all I wanted to do was get back to my wife, and rear a family, and forget it,” says Anderson, from Manchester, who went on to work for an advertising agency.

Visiting the cemeteries would be hard, he says. “I know I am not going to like it when we get to Omaha and see the American cemetery. Those numbers of graves are just too much.”