It was on the last day of the worst month of the worst year of the Troubles that three IRA bombs exploded in the village of Claudy, Co Derry.
The carnage was terrible: nine people, including a little girl, were killed, bringing the overall death toll in Northern Ireland for July 1972 alone to almost one hundred. To many, it looked as if the conflict would escalate out of all control.
Yesterday an official report confirmed that the police, the British government and Catholic Church conspired to protect the prime suspect: a Catholic priest. But it also revealed the profound moral and political dilemma which faced all those involved: the arrest of a Catholic clergyman would likely have inflamed an already dire political and security situation, but the failure to apprehend him risked hampering the search for justice for those who were killed.
Within days of the attacks, there was strong intelligence that one of the bombers was Fr James Chesney, the local republican quartermaster and "director of operations." William Whitelaw, then the Secretary of State for Northern Ireland, decided in consultation with the Archbishop of Armagh, Cardinal William Conway, that the priest should not be arrested but instead discreetly transferred across the border into the Republic.
The present Secretary of State, Owen Paterson, said yesterday he was profoundly sorry Fr Chesney "was not properly investigated for his suspected involvement in this hideous crime, and that the victims and their families have been denied justice". But he added: "I recognise of course that all those involved in combating terrorism at the time were making decisions in exceptionally difficult circumstances and under extreme pressure."
The Bishop of Derry, Seamus Hegarty said yesterday he was "shocked and ashamed" that a priest would have been associated with the bomb attack, though the church insisted it had not been party to a cover-up.
The Police Ombudsman, Al Hutchinson, reported he had found no evidence of criminal intent by anyone in the government or the church, but added that he had unearthed collusion. He said the decision not to pursue the priest was "wrong and contrary to a fundamental duty of police to investigate those suspected of criminality".
Mr Whitelaw and Cardinal Conway are both dead but the Ombudsman recovered material from their files and diaries. While their exact thought processes remain unknown, the signs are they quickly agreed that Fr Chesney should be transferred.
There were many ecclesiastical precedents for moving priests – as has been seen in its reactions to various child-abuse scandals. In addition, in the months before Claudy, loyalists had begun to kill Catholics in large numbers. The emergence of an active IRA priest could quite possibly have encouraged them to kill clergy.
From the government's point of view, the idea a priest was an active terrorist would have made far more difficult its attempts to persuade Catholics and Protestants to co-operate in a new partnership government. Furthermore, the arrest of a priest could have caused uproar, since many Catholics would have found it impossible to believe he could be a bomber.
A sense of the tensions of the time was given in the memoirs of the then Prime Minister, Edward Heath, when he wrote: "I feared that we might for the first time be on the threshold of complete anarchy."
The Cardinal seems to have been persuaded by a file shown to him by Mr Whitelaw which referred to Fr Chesney's involvement in Claudy and other acts of terrorism. According to an official document, the Cardinal said "that he knew the priest was a very bad man". In his diary, the Cardinal described the meeting as a "rather disturbing tête-à-tête". He also reported that in interviews with churchmen, Fr Chesney had strenuously denied any involvement in the IRA. Some state documentation showed that some individual police officers pushed for him to be arrested, even at the cost of causing a major stir.
One Special Branch detective inspector wrote in a memo: "We would need to be prepared to face unprecedented pressure. Having regard to what this man has done, I myself would be prepared to meet this challenge head-on." When the Northern Ireland Office wrote to the then Chief Constable, Sir Graham Shillington, saying it was proposed to shift Fr Chesney to Donegal, he went along with the idea, noting: "Seen. I would prefer transfer to Tipperary." By this he meant he would prefer Fr Chesney to be moved further away from Northern Ireland than Donegal, which is on the border.
Relatives of those killed were unimpressed by yesterday's report. Mark Eakin, who was blown off his feet in the blast that killed his eight-year-old sister, Kathryn, said he wanted an apology from the Government.
"An apology, yes, but... I would like to see somebody brought to justice for this," Mr Eakin said. "The families need to know how far up the conspiracy went." Mr Eakin, a Protestant, added: "I just feel so sorry for some of the Catholic people. I feel they've been let down by their church."