The UK’s domestic spy service MI5 knew that a British double agent in the Irish Republican Army (IRA) had committed murders and then tried to hinder a police investigation and “conceal the truth”, an official report found on Tuesday.

The nine-year £40 million (€46 million) probe — known as Operation Kenova — investigated actions of “Stakeknife”, a senior IRA member who was passing information to British intelligence during the conflict in Northern Ireland known as the Troubles.

Ex-intelligence agents had described Stakeknife as Britain’s most centrally placed mole in the IRA. He was allegedly allowed by British Army intelligence officers to interrogate, torture and kill IRA colleagues to maintain his cover as the group’s internal security chief.

British media identified Stakeknife in 2003 as Belfast IRA veteran Freddie Scappaticci, who denied the allegations until his death in 2023 at the age of 77. He is not identified as Stakeknife in the Operation Kenova report due to state policy of not naming agents.

The investigation, led by former Police Scotland chief constable Sir Iain Livingstone, found that MI5 was “closely involved in Stakeknife’s handling”. The agency had previously said its role in connection with the double agent was “peripheral”.

Operation Kenova examined scores of killings and abductions linked to the IRA’s notorious “Nutting Squad,” which was responsible for interrogating, torturing and killing people suspected of passing information to British security forces during the conflict.

‘Conceal the truth’

The report stated that Stakeknife was “often very frank with his handlers concerning his direct involvement in serious criminality including murder”. He was implicated in 14 murders and 15 abductions, according to the probe.

It found that Stakeknife’s actions probably cost more lives than they saved.

“The protection of the agent was apparently more important than protecting those who could and should have been saved,” the report said.

Stakeknife’s handlers twice took him out of Northern Ireland for a “holiday” when they knew he was wanted by police on suspicion of murder and false imprisonment, it found.

The details came to light in hundreds of documents MI5 discovered in April 2024.

“The revelation of the material was the culmination of several incidents capable of being negatively construed as attempts by MI5 to restrict the investigation, run down the clock, avoid any prosecutions relating to Stakeknife and conceal the truth,” the report said.

Following the publication of the report, MI5 Director General Ken McCallum offered sympathies “to the victims and families of those who were tortured or killed by the Provisional IRA’s internal security unit during the Troubles”.

More than 3,600 people died and some 50,000 were wounded in the three decades of conflict involving Irish Republicans, British loyalist militants and the UK security forces. The 1998 Good Friday Agreement largely ended the violence in Northern Ireland.