Taoiseach Micheál Martin has named Freddie Scappaticci as the former British army agent known as Stakeknife in the Dáil this afternoon.
During statements on the Report of Operation Kenova, Mr Martin said Stakeknife's identity was "clear to everybody" in the chamber.
The Kenova Inquiry, which linked him to murders, kidnap and torture, wanted to name him but was prevented doing so.
That is because the British government adheres to a policy of 'Neither Confirm Nor Deny' when it comes to agents and refused the necessary authorisation.
However, Mr Martin this afternoon called on the British government to officially name Stakeknife as Scappaticci.
Mr Martin told the Dáil: "It is widely known that Stakeknife was Freddie Scappaticci. He was recruited by the British army with whom he worked between the late 1970s and 1990s.
"He was a prized informant and during this period the British army dedicated a 24-hour phoneline within its intelligence section to his cause."
Mr Martin said that during this period, Stakeknife was implicated in "grotesque and serious crimes committed for and with the Provisional IRA".
He told the Dáil that this included 14 murders and 15 abductions.
Scappaticci, who was from west Belfast, died in 2023.
The Dáil heard statements on the final Operation Kenova report, which was published in December.
The report revealed that the agent 'Stakeknife' was involved in murders and torture, likely costing more lives than he saved.
The Taoiseach said the report relates to "a terrible period in the history of our island".
But Mr Martin insisted that "the past must not be hidden".
Mr Martin welcomed today's debate in the hope that it would give the Kenova Report "the attention it deserves".
He strongly criticised leaders of the republican movement including Sinn Féin and warned against any revisionism when considering this difficult period.
"Unfortunately, we have been unsuccessful in the past three decades in getting certain elements and organisations to be open and honest about the behaviour of their members and supporters."
The Provisional IRA "were a scourge on all communities", he said, adding that the report concluded that they acted to "to intimidate and subjugate the nationalist and republican communities across the North".
Mr Martin said that this was the intent of the IRA - and of "those who endorsed it - Sinn Féin", adding that "no amount of aggressive revisionist history from its supporters will ever erase their crimes against their own community".
"More than 25 years after the Good Friday Agreement it is staggering," he said, that the report states: "that republican leadership have failed to acknowledge and apologise for the PIRA's murderous activities".
Indeed, he said that now "public figures honour the PIRA but launch legal cases against anyone who points to the vicious crimes which were committed".
Sinn Féin leader Mary Lou McDonald said: "To all those that suffered such grievous loss, I am sorry for all the lives lost during the conflict and for the hurt and loss endured without exception.
"Those words reflect a genuine sense of sorrow and regret for everyone who was hurt and harmed during those years of violence.
"By that I mean civilians, combatants and families whose lives were forever changed."
The findings of the Kenova Report are "stark and deeply disturbing", she added.
They confirm that "collusion was not an aberration but a defining feature of British state policy during the conflict".
It was a deliberate political choice that cost lives, the deputy said.
Labour Party leader Ivana Bacik said that Kenova "made real testimony central" and "saw real accountability".
Trust in institutions has been damaged, she said, and "Kenova tells us how we can honour the rights of victims to truth and justice".
"A failure to implement Kenova's recommendations will erode trust further," she warned, and urged that dealing effectively with the legacy of the conflict must "permeate the tone of our politics" across the island.
Social Democrats TD Sinéad Gibney notes the report's confirmation of "deplorable collusion" which caused 127 deaths.
"There is still a need for further clarity," she said.
She condemned the failure of the British government to name Stakeknife.
"Information is desperately needed," she said, and warned that "to withhold it invites a continuation of grievance."
Minister for Justice Jim O'Callaghan detailed some of the many "shocking" findings in the Kenova Report.
He emphasised that investigations remain open in "all unresolved Troubles-related cases", including the death of 38-year-old father-of-three John Hayes who was killed in the Dublin Airport bombing in 1975, and whose case is less well known.
Earlier this week, a cross-party group of MPs called on the British government to name the former British army agent known as Stakeknife, saying it would be "appropriate, proportionate and strongly in the public interest".
Thompson Supreme Court case
A spokesperson for the British government said it was not yet in a position to formally respond to the request by Operation Kenova to name Stakeknife.
In a statement to RTÉ News, the spokesperson said this was due to ongoing litigation and the consideration of a recent judgment in the Thompson Supreme Court case.
The Thompson case refers to a judgment handed down by the UK's highest court which prevented the disclosure of intelligence information by an inquest into loyalist murder of Paul Thompson in west Belfast in 1994.
The spokesperson said that Northern Ireland Secretary Hilary Benn has committed to updating the British parliament "as soon as he is able to".
The spokesperson added: "The behaviour described in Operation Kenova's final report is deeply disturbing. It should not have happened, and in recent decades, there have been significant reforms to agent handling practice, including through legislation. The use of agents is nowadays subject to strict regulation, overseen by the Investigatory Powers Commissioner and the Investigatory Powers Tribunal."
