It took 50 years, but on Wednesday, the UK Supreme Court recognised that 14 men held without charge in Northern Ireland in 1971 were tortured.
The court unanimously found it likely that "the deplorable treatment to which the Hooded Men were subjected at the hands of the security forces would be characterised today, applying the standards of 2021, as torture".
The "Hooded Men" were so called because they were hooded when singled out for "in-depth interrogation" after being picked up from their homes in August 1971.
Britain had initiated a policy of interning people without charge or trial in Northern Ireland. On 9 August 1971, 342 people were arrested in one day. All were from the Catholic, nationalist community. Their crimes? Unknown.
Those arrested were first brought to detention camps at army bases and police barracks. Within two days, over a hundred were released. The rest were interned.
Over three days, 21 people died – 17 shot by the British Army, including 11 in what is known as "the Ballymurphy massacre".
Over the following four years, almost 2,000 were interned.
Many were put through special military "softening-up exercises" – beatings, deprivations and degrading treatment later catalogued in detail for the Irish Government as it prepared to take a case under the European Convention of Human Rights.
But it was the special selection of 14 internees in August 1971 for days of in-depth interrogation that stood out.
The story of those 14 detainees featured in the 2014 RTÉ Investigates documentary The Torture Files.
Five main torture techniques, honed by the British army in former British colonies such as Aden, Malaysia, Borneo and Kenya, were used against them in a systematic, planned operation.
We shall have to fight them at Strasbourg by every means open to us. Dublin will regret it
The five techniques were hooding, hours of wall standing, white noise, sleep deprivation and deprivation of food and water.
They were taken by helicopter to a purpose-designed interrogation facility – official records put its location at Ballykelly airbase near Derry – with its own operations room, monitoring room, noise generators, amplifiers, noise decibel specifications and standing orders.
What happened there was code-named "Operation Calaba" and controlled and overseen by a team of 15 from the British Joint Services Interrogation Wing. The police force, the RUC Special Branch, were involved in a support role.
The 14 men were a mixed bag, but they had one thing in common: No charges or convictions arose from their detention.
Ireland took their case and others to the European Court of Human Rights in Strasbourg for breaches of Article 3 of the European Convention, the absolute prohibition on torture.
The state was advised by Professor Robert Daly, then a professor of psychiatry at University College Cork. He had documented the involvement of psychiatrists in perfecting methods of interrogation by torture.
Prof Daly later told RTÉ Investigates that each of the five techniques used against the Hooded Men could bring about "psychosis and breakdown" on their own.
"The package altogether was pretty disastrous, so it was rather sanitised to call it the five techniques," he said.
An internationally renowned psychiatrist, Prof Jan Bastiaans, a specialist of trauma who had examined hundreds of captives of World War II prisons and concentration camps, also advised the government for the European case.
"Interrogation in depth", he wrote, "is a new term for brainwashing."
In his 1972 report on the techniques used in Northern Ireland, Prof Bastiaans wrote: "Nearly anyone can be reduced to a state of helplessness, dependency and even mental illness if the right techniques are used."
"The physical results of such treatment are severe enough, and some may be permanent", he advised.
"The mental effects are much more difficult to predict, but the effects of terror are seldom entirely transient."
Britain fought the case hard. On 22 August 1973, its Conservative prime minister, Ted Heath, wrote: "We shall have to fight them at Strasbourg by every means open to us. Dublin will regret it."
In 1978, the European Court of Human Rights found Britain guilty of inhuman and degrading treatment, but not torture. "A special stigma", it said, was attached to that word, and the treatment of the detainees did not cause suffering of the particular intensity and cruelty implied by the word torture.
From 1972, the legal advice to the Heath administration was that what they had approved was illegal and that ministers could be liable to conspiracy.
UK archives show just how far civil servants and security personnel went to shield cabinet ministers from being made accountable for the policy.
Documents from those archives were revealed by RTÉ Investigates in June 2014.
For the first time, the investigation, The Torture Files, identified senior ministers of the British cabinet of 1971 as having given informed authorisation for the planned, systematic operation of the 'in-depth' techniques.
They included the Secretary of State for Defence, Lord Peter Carrington, the Home Secretary, Reginald Maudling, the Minister for Home Affairs in Northern Ireland, Brian Faulkner, and the Minister of State for Defence, Robert Lindsay, who was styled as Lord Balniel at the time.
One document from the UK archives summed up what other records demonstrated: writing to his prime minister Jim Callaghan in 1977, the then-Home Secretary, Merlyn Rees, wrote that "the decision to use methods of torture in Northern Ireland in 1971/72 was taken by ministers – in particular Lord Carrington, then Secretary of State for Defence."
It became known as the "Rees memo". On foot of the 2014 programme, the then-Minister for Justice Charlie Flanagan and Taoiseach Enda Kenny's government asked the Strasbourg court to revise its judgment in the 1970s Ireland v United Kingdom case.
It declined. In 2018, the European Court of Human Rights held that it had to base its rulings on case law in the 1970s, not those of today.
It also did not accept that there was a significant distinction between 'high level' authorisation of the techniques, which Britain had conceded in the case, and 'ministerial' authorisation.
However, in 2019, by a majority, the Northern Ireland Court of Appeal accepted that archive documents showed the UK admitted to "high level" authorisation to avoid any detailed inquiry – and that it opposed hearing witnesses on the five techniques to avoid exposing the Cabinet ministers involved.
That Court of Appeal judgment arose from a case taken in 2015 by one of the surviving Hooded Men, Francis McGuigan, and Mary McKenna, the daughter of another, the late Séan McKenna.
Ms McKenna sought judicial review of a 2014 PSNI decision that there was no evidence to warrant an investigation in whether the British government authorised torture.
The Court of Appeal ruled that the police must fully investigate the allegations revealed by RTÉ Investigates. It held that a PSNI investigation that formed the basis of the decision not to investigate further, was "inadequate", "unduly narrow" and "irrational".
The PSNI appealed that to the UK Supreme Court, which led to its judgment on Wednesday.
For the PSNI, the investigatory issue arose from a promise made a month after the RTÉ Investigates revelations, on 3 July 2014, when the then-Chief Constable of the PSNI, George Hamilton, said there would be an investigation, and then Assistant Chief Constable, Drew Harris, told the Northern Ireland Policing Board that the matter had been passed to the HET, the PSNI's Historical Enquiries Team.
He stated that the PSNI has been made aware by the RTÉ documentary of the existence of the Rees Memo and that the PSNI wished to source the original document and other materials in order to confirm or further clarify its contents.
The investigation identified senior British ministers as having given informed authorisation for the planned, systematic operation of the techniques
The HET tasked an investigating officer who was brought in to draw up a report. Commenting extensively on the report in its judgment of this week, the Supreme Court of the United Kingdom agreed with the majority Northern Ireland Appeal Court.
It quashed that PSNI decision as unlawful and "irrational", because the police report it relied on to make the decision was "seriously flawed".
The UK Supreme Court found that the report "shows on its face a lack of fairness in the officer's approach and a willingness to base conclusions on partisan assumptions rather than evidence".
It said it contained baseless speculation and noted that it suggested that this reporter could not have inspected the Rees Memo in the National Archives, because "this document has, in effect, been retained under secure conditions since 1978".
This is despite the fact that a photograph the reporter took of the Rees Memo in the national archives was shown on screen in the RTÉ Investigates documentary.
"The investigating officer felt able to make outspoken criticisms of the RTÉ documentary" but his own statements and assumptions indicated he had not even watched the programme, the Supreme Court found.
It was this flawed report that the PSNI relied on to make its decision not to pursue an investigation. The investigating officer's report was completed and forwarded to the Assistant Chief Constable's office by the head of the HET, Detective Chief Superintendent Brian Hanna.
In early October 2014, a letter was drafted from the Assistant Chief Constable, Drew Harris, to lawyers for the Hooded Men, that the matter had been "researched and reviewed by the Historical Enquiries Team, who have not identified any evidence to support the allegation that the British government had authorised the use of torture in Northern Ireland".
On 13 October 2014, Drew Harris was promoted to Deputy Chief Constable of the PSNI. Four days later, on 17 October 2014, his successor as Assistant Chief Constable, Will Kerr, issued a decision letter to the Hooded Men's lawyers, in the same terms.
Asked to comment on the Supreme Court findings on the "seriously flawed" PSNI investigation, the Garda Press Office said Drew Harris, who is now the Commissioner of An Garda Síochána, "was not an Assistant Chief Constable on 17 October 2014".
As such, the UK Supreme Court's reference to the decision by the Assistant Chief Constable of 17 October 2014 does not refer to him, it said.
With respect to any new investigation, the ball is now back in the PSNI's court.
Notwithstanding the flawed investigation of 2014, the UK's Supreme Court held that there is nothing to suggest that it would not be possible to assign appropriate officers of the PSNI to carry out any further investigations to a proper standard.
It was this flawed report that the PSNI relied on to make its decision not to pursue an investigation
The Hooded Men case has had a long tail: There are the records of legal advice to the British government of the 1970s, advising that what it had authorised was illegal. There is the partisan and flawed 2014 report that the PSNI relied upon not to pursue an investigation.
But there is very little to inspire confidence that either justice will be done, or that the absolute prohibition on torture in international law has not been severely undermined over many years.
The legal judgment in the Ireland v UK case itself has also had a long tail. It set precedent for how torture was legally distinguished from "inhuman and degrading treatment".
Prime Minister Ted Heath officially declared the five techniques banned in 1972, and in 1978, Labour's Jim Callaghan administration assured the Strasbourg court that the techniques would not be used again.
But they were.
In 2003, the US Attorney General's office used the judgment to provide legal cover for the Bush administration's use of torture in Iraq, Afghanistan and Guantanamo Bay, advising that Ireland v UK permitted "an aggressive interpretation" of what constitutes torture under international law.
In 2011, a statutory public inquiry in the UK found the five techniques had again been used by every British battle group during the invasion of Iraq in 2003.
Speaking to RTÉ Investigates in 2014, the retired Commander Legal of British Forces in Iraq in 2003, Lieutenant-Colonel Nicholas Mercer, recalled that he saw Military Intelligence running an "interrogation in-depth" camp there, with 40 prisoners, hooded, some in stress positions, and generators running outside the interrogation tent.
He said he took it up with the interrogation team.
The interrogators, he said, responded: "Well, we don't answer to you. We answer to London."
Perhaps London has a lot to answer for.
Watch the 2014 RTÉ Investigates documentary, The Torture Files.