Veterans of the British army’s 38-year deployment in Northern Ireland gathered at a rain-sodden memorial in England on Wednesday after the defence secretary said those who served should not fear prosecution when no new evidence has emerged.

In carefully worded remarks, Ben Wallace said that “veterans in their 70s and 80s” should not be “dealing with the trauma of waiting for a knock on the door where there is no new evidence that an offence has been committed”.

The minister was the most senior political figure present at the commemoration at the National Memorial Arboretum in Staffordshire, and his remarks were widely welcomed at an event described as a family reunion by one of those attending.

Around 300,000 military personnel served in Northern Ireland as part of Operation Banner, which began in August 1969. An estimated 3,600 people were killed during the 30-year Troubles, including 1,441 members of the armed forces.

The idea of an amnesty for soldiers remains controversial in the nationalist community because it appears one-sided, although some believe it could be justified if it was extended to cover former paramilitaries.

The defence secretary, Ben Wallace, at the event at the National Memorial Arboretum in Staffordshire. Photograph: Jacob King/PA

One veteran present at the event, Nick Cross, who served several tours in Northern Ireland between 1970 and 1976 as a military policeman, said it was time to draw a line. “It makes sense to apply it to everybody. We should have done something similar to what happened in South Africa with the truth and reconciliation commission.”

Sitting in the late 1990s, the TRC illuminated horrors committed under white minority rule in South Africa, where perpetrators were able to confess their crimes in hearings broadcast live on television in return for the promise of an amnesty for politically motivated violence.

The service in Staffordshire, presided over by the newsreader Alastair Stewart, was a secular event organised by the Royal British Legion rather than the government, with Wallace the only senior minister present.

Cross, originally from Blackburn, signed up in Liverpool at the end of the 1960s where “I’d ended up penniless”, he said. A year later, aged 20, he was deployed in Belfast and said “nobody had any idea what we were supposed to be doing”.

Cross said he believed initial goodwill in 1969 from large sections of the Catholic community was too rapidly squandered, and that the growing tensions were catastrophically worsened by the introduction of internment in 1971.

“It was the most crass, ill thought-out operation conducted by the British army ever,” he said. At one point during internment – military detention without trial - he was sent to a border farm near Strabane to arrest a man.

“There were four men there, playing cards. I asked them which one was the man I was after, and one by one they all said they were. So I said to the lieutenant who was with me, ‘take the lot of them’.”

Cross left Northern Ireland in 1976 after he was nearly killed by a car bomb on the Falls Road. “We were driving past in a military vehicle and if that bomb had gone off two seconds later, we’d have been blown to bits.”

At first he went to work at Nato’s allied command in Belgium “because all I was good for was opening car doors for people” before leaving the armed forces. Subsequently he says he suffered from PTSD which was “never recognised by the army then. People just said ‘go for a drink’.”

Cross said he believed the contribution he and the other military personnel who served in Northern Ireland provided did help eventually secure peace, and that it was important it was recognised.

“I do think we made a difference in the end. You have to think that, otherwise it negates a large percentage of a young person’s life,” he said.