Military veterans, families of those who died and politicians are calling for the focus of the D-day commemoration in Portsmouth to be on those who fought rather than on the controversial presence of Donald Trump.

A vast security operation to safeguard the US president and other dignitaries, including Theresa May and the Queen, has been put into place on Southsea Common, the venue for the centrepiece of the British ceremonies to mark the 75th anniversary of the Normandy landings.

Miles of fencing, roadblocks and checkpoints have been set up and residents have been told not to aim long-lens cameras at Wednesday’s event from nearby flats or fly drones over the common.

'I count myself lucky': D-day remembered on the 75th anniversary Read more

Protests are planned both at the edge of the ring of steel and a mile from the common in Portsmouth’s Guildhall Square, but the hope from most is that the circus around Trump will not overshadow the principal purpose – to honour the sacrifice of those who took part in D-day.

At the D-day Story museum in Southsea, its manager, James Batney, said the buildup to the big day had been moving and wonderful.

“We’ve had a real mix of people of all ages and all nationalities arriving,” he said. “The other day, a group of veterans was sitting out in the sun. Children were coming up to ask for photos. Then a coach full of American tourists stopped. Every one of them that got off the bus went and shook hands with the veterans. This is the last big date when we’ll have so many veterans.

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

“Donald Trump is a divisive figure but from my point of view, the president of the US has been invited to join in the commemorations of Europe being freed from the tyranny of fascism. For me it doesn’t really matter who the president is in that context. It’s about the post rather than the person.”

Facebook Twitter Pinterest Miles of security fencing has been erected around Southsea Common in Portsmouth. Photograph: Andrew Matthews/PA

Ernie Nelson, a 95-year-old veteran from Cheshire, said it was “first class” to be back in Portsmouth for the 75th anniversary. Nelson was a wireless telegraphist on HMS Scourge, which escorted convoys to Sword beach and provided fire support to troops when they landed.

“A lot of memories come back to me, that’s the trouble,” he said. “I get flashbacks, I remember the people I was with at that time.” His daughter, Susan Conneely, said this was not the time or place for demonstrations: “It’s all about remembrance, it’s not about politics.”

Letitia Abbott, a US citizen, was in Portsmouth to remember her father, Jack, who landed at Omaha beach on D-day. “He was deeply affected,” she said. “He would talk about it but he couldn’t do some things, such as go to the movies, for years after. It was just too much for him. I’m here because I loved my father and I wanted my son [also Jack] to come here and understand it all.”

Abbott said it was right that the US president should be present but she was sad it was Trump who was in office. “This is the guy with bone spurs who couldn’t fight in Vietnam.”

The event on Southsea Common will tell the story of the buildup to D-day through live music, performance and testimonials. Those not invited will be able to watch on big screens on the common, although some residents feel they have been pushed away from it because of the security.

Hundreds of veterans will attend the ceremony and up to 300 will board a cruise ship, the MV Boudicca, later on to retrace their route to Normandy 75 years ago accompanied – as they were then – by a flotilla of Royal Navy vessels.

The leader of Portsmouth council, Gerald Vernon-Jackson, said he hoped the protesters would stay away from the common and the Tory group leader in the city, Donna Jones, said demonstrations would make the event about Trump rather than the veterans.