Kenova was a major investigation into the operation of the British Army’s top agent inside the IRA, headed up by Mr Boutcher before he left to take up the PSNI role last year.

Operation Kenova examined 101 murders and abductions linked to the Provisional IRA’s so-called ‘nutting squad’.

Kevin Winters, who represents 12 families directly impacted by the report, said there now needed to be a public inquiry.

The agent in the internal security unit of the IRA is widely believed to be Belfast man Freddie Scappaticci.

Northern Ireland’s Public Prosecution Service concluded there was insufficient evidence to provide a reasonable prospect of conviction.

The four were reported to the PPS for consideration across six files submitted by Operation Kenova investigators.

Stakeknife worked within the IRA’s notorious ‘nutting squad’, interrogating suspected informers during the Troubles.

Stakeknife worked within the IRA’s notorious “nutting squad”, interrogating suspected informers during the Troubles.