A High Court judge has ordered Downing Street to hand over minutes of cabinet meetings related to the Government's decision not to hold a public inquiry into the murder of Belfast solicitor Pat Finucane.
Mr Justice Stephens ruled today that he should first inspect a series of documents and e-mails being sought as part of a legal challenge to the refusal to order a full, independent inquiry into the 1989 assassination.
Confidentiality issues will not make them immune from disclosure, he pointed out.
The murdered lawyer's widow Geraldine wants full access to the material, including minutes from cabinet meetings and correspondence between Downing Street officials.
A review carried out by lawyer Sir Desmond de Silva QC has confirmed agents of the state were involved in the murder and that it should have been prevented.
However, it concluded there had been no overarching state conspiracy in the shooting, carried out by the loyalist Ulster Freedom Fighters at the solicitor's north Belfast home.
Although Prime Minister David Cameron expressed shock at the level of collusion uncovered by Sir Desmond, Mrs Finuncane claimed it was a sham and a whitewash.
During her application for complete disclosure of notes and recordings the court was told of emailed correspondence where one of Mr Cameron's closest advisors described the murder as far worse than anything alleged in Iraq or Afghanistan.
Sir Jeremy Heywood, now the Cabinet Secretary, also questioned whether the Prime Minister believed it was right to "renege" on a previous administration's commitment to hold a public inquiry into a killing he referred to as "a dark moment in the country's history", Mr Justice Stephens was told.
Lawyers for the Finucane family argued that the case is about past and present abuse of state power.
They alleged that it involved the killing of a solicitor perceived to be "a thorn in the side" of the government, police and security services.
It was claimed that a further abuse of power occurred in 2011 when the current government went back on a commitment to hold a public inquiry.
The court heard details of an e-mail Sir Jeremy sent to Simon King, a private secretary to the Prime Minister, ahead of a ministerial meeting in July 2011.
In correspondence already disclosed to the parties, he asked: "Does the PM seriously think that it's right to renege on a previous government's clear commitment to hold a full judicial inquiry?
"This was a dark moment in the country's history - far worse than anything that was alleged in Iraq/Afghanistan.
"I cannot really think of any argument to defend not having a public inquiry. What am I missing?"
A reply e-mail stated that the Prime Minister "shares the view this is an awful case, and as bad as it gets, and far worse than any post 9/11 allegation".
Material being sought by the Finuncanes' lawyers includes original notes, minutes, recordings or transcripts of:
:: A meeting between the Secretary of State for Northern Ireland and Prime Minister on November 5, 2011.
:: A meeting of officials from the Northern Ireland Office, Cabinet Office and Prime Minister's Office on May 16, 2011.
:: A meeting of ministers on July 11, 2011.
:: A Cabinet meeting on October 11, 2011.
:: Copies of letters from MI5 to the Northern Ireland Office in February and Macrh 2011.
Delivering judgment on the discovery application, Mr Justice Stephens held that Mrs Finucane's legal team had established sufficient necessity.
He said: "I direct that I should receive and inspect the outstanding documents, so that I may decide whether disclosure would give sufficient extra assistance to the applicant's case, over and above the material that has already been furnished."
Further submissions are to be made on any redactions required should he ultimately decide the material should be handed over.