The recognition by David Cameron of a long-standing truth, in language as unequivocal as the Bloody Sunday report upon which it was based, restored faith, hope and life into a community that had laboured under a long shadow cast by unfounded innuendo.

Combined with a full apology, it liberated the spirit of families who have been imprisoned for 38 years by an injustice perpetrated by the British state.

The concluding paragraph of Lord Saville's overall assessment was: "The firing by soldiers of 1 Para on Bloody Sunday caused the deaths of 13 people and injury to a similar number, none of whom was posing a threat of causing death or serious injury. What happened on Bloody Sunday strengthened the Provisional IRA, increased nationalist resentment and hostility towards the Army, and exacerbated the violent conflict of the years that followed. Bloody Sunday was a tragedy for the bereaved and the wounded, and a catastrophe for the people of Northern Ireland."

As the Prime Minister pointed out, these were shocking, indefensible events, especially because they were underpinned by the perpetrators' false accounts. These have been upheld across 38 years and two public inquiries. They will need to be scrutinised by the prosecuting authorities as well as by the consciences of individual soldiers. For the sake of truth and reconciliation, it is hoped that integrity will finally compel those who fired to put the record straight.

There is, however, one major element in this catastrophe that has been largely overlooked – the responsibility of Lord Widgery and his team during the first Bloody Sunday inquiry in April 1972. This was never part of Lord Saville's remit. Nevertheless, the Widgery report compounded the felony and inflamed bitterness for generations to come. In a Channel 4 television programme entitled Secret History: Bloody Sunday broadcast in 1992, Bishop Daly said: "What really made Bloody Sunday so obscene was the fact that people afterwards, at the highest level of British justice, justified it."

This failure also needs to be acknowledged. No system of justice is worthy of its professed principles if, as soon as it is under pressure, its independence and judgement evaporates.

The flawed Widgery report cannot be easily explained away. It was not compiled by someone of inexperience or weak disposition. There was no lack of resources and, importantly, all the necessary evidence was available.

We now know through documentation which came to light subsequently that hundreds of civilian eyewitness statements were ignored or marginalised. Glaring inconsistencies in the accounts of the firers were either not disclosed or barely challenged. It was alleged there were 15 engagements, of which nine targets were either nail or petrol bombers, the rest were gunmen. The shot list was totally unsatisfactory. The grid references did not make sense. Lord Saville's conclusion was succinct. First, "no one threw, or threatened to throw, a nail or petrol bomb at the soldiers on Bloody Sunday. Second, all the soldiers, apart from private T, who were in our view responsible for the casualties insisted that they had shot at gunmen or bombers, which they had not..."

In 1995 a letter was found in the Public Record Office in London. It contained a minute of a meeting between Lord Widgery, Edward Heath, then Prime Minister, and the then Lord Chancellor on 1 February 1972. Among many items, Mr Heath noted that "It had to be remembered that we were in Northern Ireland fighting not only a military war but the propaganda war."

The system of justice must never again allow itself to be subverted.