Two former British army paratroopers accused of murdering an Official IRA commander during the Troubles have been acquitted after their trial in Northern Ireland collapsed. The two veterans, known as soldiers A and C, had been accused of murdering Joe McCann on 15 April 1972, in a closely watched trial with political ramifications. The case collapsed when the Public Prosecution Service decided not to appeal against a decision by Mr Justice O’Hara to exclude some evidence as inadmissible. The result delighted army veterans’ groups and their supporters, who said the case was the latest example of old soldiers being subjected to a politically motivated witch-hunt. McCann’s family said justice had been denied. McCann was a member not of the Provisional IRA but its republican Marxist rival, the Official IRA. He was photographed in 1971 holding a rifle beside the Starry Plough, the flag of the Irish labour movement. A year later when a Royal Ulster Constabulary officer tried to arrest McCann, he fled, prompting soldiers A and C and a now deceased paratrooper, soldier B, to open fire, hitting the 24-year-old in the back. The case hinged on whether the force used was reasonable. Prosecutors said soldiers A and C believed McCann was armed but they found no weapon. A defence lawyer said McCann was suspected of murders and could have committed more if he had evaded arrest, leaving the soldiers with a “binary choice” of shooting to effect the arrest or letting him escape. The prosecution’s case relied on statements the ex-soldiers gave to the Royal Military Police – without caution – in 1972 and to Northern Ireland police in 2010. Prosecutors accepted there were deficiencies in how the original statements were taken but said they should be used given that the defendants accepted them during questioning in 2010. Mr Justice O’Hara said the court could not accept the 1972 statements even if “dressed up” in a 2010 cover – a decision prosecutors decided to not appeal against, collapsing the trial on Tuesday. “In the circumstances, Mr A and C, I formally find you not guilty of the charge of murder,” the judge told the accused, who remained anonymous. They walked from the court. The McCann family condemned the outcome. “This ruling does not acquit the state of murder. It does not mean that Joe McCann was not murdered by the British army. It is proof that the British army operated with impunity for their crimes,” their solicitor said in a statement. Dolores Kelly, the SDLP’s policing spokesperson, said the police and prosecutors had questions to answer. “At the heart of this catalogue of failures is a family who have been let down by the processes of justice. Their pain has been deepened today,” she said. The Public Prosecution Service defended its handling of the case and said there had been a reasonable prospect of conviction. Johnny Mercer, who quit his post as the UK’s veterans minister last month in protest at the prosecution of veterans in so-called legacy cases, attended the trial and welcomed the result. “Hopefully this marks the lowest point in this nation’s treatment of her veterans,” he tweeted. “Government must act.” Army veteran campaign groups celebrated the result, calling it a precedent for any prosecutions of other soldiers. At least four other cases involving veterans are at the pre-trial stage. Unresolved killings from the Troubles have dogged policing and politics in Northern Ireland and in London, where consecutive UK governments have wrestled with whether and how to shield as many as 200 former members of the security forces from potential prosecution. Sinn Féin accuses the British state of covering up state-sanctioned murder in cases ranging from Bloody Sunday to the shooting of the solicitor Pat Finucane in 1989. Unionists and veterans groups accuse Sinn Féin and its allies of abusing the legal system to harass former security personnel and rewrite history. The Police Service of Northern Ireland says it is caught in the middle and that another agency should investigate historical cases. The next landmark legacy case will unfold on 11 May when the Belfast coroner delivers the result of a two-year inquest into the killing by soldiers of 11 people in Ballymurphy, a west Belfast neighbourhood, during two days in August 1971.