By Dominic Casciani
BBC News Online at the National Archives
Ministers were warned before its publication that the original Bloody Sunday inquiry's findings fell short of the expected standard.
1972 saw civil rights marches in Northern Ireland
Documents from 1973 reveal the then Northern Ireland Secretary wanted the event "buried as quickly as possible".
But he was warned the inquiry into the 1972 shootings was sufficiently flawed to encourage critics.
The second Bloody Sunday inquiry is continuing.
Lord Widgery, the then Lord Chief Justice of England, was asked by Prime Minister Edward Heath to investigate the 13 shootings by the Parachute Regiment at a 1972 civil rights march in Londonderry.
Weeks before it was due to be made public, Lord Grey of Naunton, the Queen's representative in Northern Ireland and its last governor, asked to speak urgently with Northern Ireland Secretary William Whitelaw.
"With respect to the very eminent Lord Chief Justice, I do not think the report is as clear crisp and comprehensive as the report of the Scarman Tribunal," he said in a letter to the minister.
"I think those who are out to show that Britain and her army and 1 Para [the unit whose soldiers fired] in particular were much in the wrong will be able to mount an attack."
In 1969, London had forced the Unionist-controlled Stormont government to accept the investigation by the Scarman Tribunal into the growing violence.
After two years, it published a detailed report into controversial incidents, including shootings and the behaviour of the security forces.
But according to the documents released at the National Archives, Lord Grey felt the Widgery inquiry did not come up to that standard.
In particular, he criticised Lord Widgery for taking soldiers entirely at their word on the evidence before him.
Lord Grey told William Whitelaw that the tone and conclusion of the Widgery report would only encourage complaints that some of the soldiers had lied, principally over their reports that the IRA had opened fire.
His letter listed case-by-case inconsistencies in the evidence and contradictions between Widgery's overall conclusions and his finding on each death.
In the report, Lord Widgery found no proof that those shot had been handling weapons; but he also said there would have been no deaths had the banned civil rights march not gone ahead.
While he questioned the judgement of some soldiers, he largely vindicated their actions, having no doubt they had been fired upon.
Concerns in Whitehall
William Whitelaw appears to have taken some of these concerns on board in meetings he had in London with other ministers and army officials.
Weeks before publication, a civil servant records him urging the Ministry of Defence to pay compensation to at least some of the dead.
"The Secretary of State for Northern Ireland felt that it was important that the memory of 'Bloody Sunday' should be buried as quickly as possible," wrote the official.
"In the current climate this was a strong argument for settling the seven cases rather than fighting them."
In another meeting, the minister warned "the army may be under-estimating the risks of adverse publicity" and were taking "too rosy a view" of the outcome.
The Widgery report was published on 19 April 1973.
Revealing its details to Parliament, Prime Minister Sir Edward Heath said: "All shades of opinion sincerely concerned with the truth must feel indebted to him for his objective and painstaking analysis of events."
But it was sparked a furious protest from families who spent the next 20 years campaigning for a fresh inquiry.
In his 2003 evidence to the new inquiry, the former prime minister denied having pressured Lord Widgery into exonerating the soldiers.