A memo recorded at Stormont on July 10, 1972 details a meeting chaired by Willie Whitelaw, Northern Ireland secretary at the time, as well as the GOC (the most senior army officer in Northern ireland), Paul Channon MP, the deputy chief constable and senior civil servants.

The document states that "The army should not be inhibited in its campaign by the threat of court proceedings and should therefore be suitably indemnified."

The Guardian reports on the newly revealed memo. The three page document - which was marked “secret” - includes a list of “conclusions” arrived upon at the meeting which immediately followed the breakdown of  the Provisional IRA’s two-week-long truce.

The memo has only recently come into possession of groups who campaign for justice for those killed on Bloody Sunday in Derry. The campaign groups have focused on re-examining the killings of those at the hands of security forces.

The document reveals that Whitelaw would "put the blame for the ending of the 'truce' fairly and squarely on the Provisionals who must now take the consequences", and "announce the government's intention to carry on the war with the IRA with the utmost vigour".

Additionally, "The GOC would see UDA [the loyalist paramilitary Ulster Defence Association] leaders and impress upon them that while their efforts as vigilantes in their own areas were acceptable, their presence in any riot or shooting situation could not be tolerated."

Mark Thompson, director of Relatives for Justice, which works for justice on behalf of victims, said: "The discovery of this document indemnifying British soldiers from the threat of court proceedings whilst they took their 'war' to nationalist communities with the 'utmost vigour' is the first official documented evidence of a policy amounting to impunity.

"It is a clear amnesty being put in place for what would later occur, the inevitable loss of life. In 1972 the British army killed 79 people. Not one soldier was held to account for these killings.

"This document provides an important insight into the mindset of the British government and those directly involved in and responsible for 'security' and its policy development – a policy that went on to have disastrous consequences for our entire community. Many observers will view this document as sectarian in its outlook and strategic approach.

"Despite their involvement in sectarian murders, the UDA was not [at that time] a proscribed organisation. They were permitted to patrol areas and exist alongside the RUC and British army at a time when intelligence would have clearly shown the UDA to be involved in sectarian murders.

That Sunday in July 1972, five people had been shot dead by republican paramilitaries. Six Catholics, including a priest, were killed by the British army.

Kevin Winters, a Belfast lawyer who represents relatives seeking justice, said: "It will lead to a request for the police's historical enquiries team to re-examine all the army killings that they have looked at to date.”

"The consequences of the document should permeate a lot of their investigations. It potentially strengthens grounds for fresh inquests. It could generate a huge amount of legal proceedings. If that was the mindset ... it would be grounds for a series of [out of time] civil actions for unlawful killings."

Paul O'Connor, of the Pat Finucane Centre in Derry, which also examines files from the period, said: "This document tells us something about the culture [at the time].”

“We deal with cases of people who were being kidnapped at UDA checkpoints and who were tortured and murdered. That ties in with allowing UDA members to join the Ulster Defence Regiment. It was the worst months of the Troubles."

Willie Whitelaw, former Northern Ireland secretaryRex