Scale of IRA's collusion with British state was shocking
It is too simplistic to paint collusion as something that took place between the state and loyalist paramilitaries. There is, in fact, a 40-year history of republicans toiling for the security services
In the lore of the IRA, there was traditionally no one more loathsome than the informer. This was thought to be the rare and despicable individual who would betray his comrades.
Some former members of the IRA now wonder if there were more informers inside the Provos than actual committed members.
Certainly, that appears to be true of the loyalists. The Stevens Inquiry reported that nearly every loyalist it spoke to was an agent.
Darragh McIntyre's BBC Panorama programme last week suggested different levels of collusion between the security forces and paramilitaries.
The most common type seems to have been the protection of agents who had killed and were likely to kill again.
On occasions, RUC Special Branch knew of planned attacks, tried to intercept them, and failed.
According to the De Silva report, they often knew of plans to murder other paramilitaries and did little to prevent these.
Furthermore, De Silva found that both the Army and Special Branch were suggesting targets to agents inside paramilitary groups, specifically to the loyalist killer Brian Nelson, since the focus of De Silva's report was the murder of solicitor Pat Finucane.
The UDA regarded Finucane as an intelligence officer for the Provisional IRA, who was engaged in money laundering.
Some in Special Branch encouraged them to target him.
No similar review of documentation has examined collusion between the state and members of the IRA - but it happened.
The De Silva report, for instance, describes efforts to protect two senior republicans.
One of them is given only a codename - 'T/02'. The other was Gerry Adams.
When Brian Nelson revealed a plan to bomb Adams by placing a limpet mine on his black taxi during the 1987 Genral Election campaign, the Army did not trust Special Branch with the information and set up its own operation to protect him.
Later, soldiers recovered the mine.
When the UDA returned to discussing how they might kill Adams, some in Special Branch appear to have suggested that Pat Finucane would be a better target.
De Silva found that state agencies justified suggesting targets to Nelson on the grounds that these attacks would absorb the energies of the loyalists and be easier to intercept. Ultimately, lives would be saved.
But they also found that Special Branch wasn't all that keen to warn a target if he was a 'thorn in the side'.
And they saw Finucane as one of those, having twice before failed to alert him to threats against him.
Another factor in the planning of the murder of Pat Finucane is that Nelson feared that if yet another attack went wrong, he would be exposed as an agent.
So, he kept the planning of the attack on Finucane secret from his handlers.
The Army itself had considered the other danger; that if Nelson was too successful in hitting senior IRA members, he would quickly be exposed.
Further, the Army would be in serious trouble if one of its agents was to kill Adams, an elected MP.
The earliest suggestion of an operation being allowed to proceed to cover for an agent was the bombing attack on London by Gerry Kelly, the Price sisters and others in March 1973.
Dolours Price, one of the bomb team, said in later years that the mission had been compromised and that someone close to the planning of it in Belfast had betrayed it.
Even so, Kelly and the Price sisters and the rest of the team were not arrested until after planting their bombs.
By 1972, the IRA was realising that it was going to have to kill an awful lot of people in the Catholic community to stop intelligence leaking out about them and that's when it hit on the idea of 'disappearing' suspects, rather than dumping their bodies in back alleys.
Three times they had just dumped the body and then said nothing.
That's what they did with John Kavanagh, Martin Owens and Sam Boyd. Those killings have never been explained.
On the same day that they detained Kevin McKee and Seamus Wright to 'disappear' them, Provos went into the club where William Bonner was drinking and lined everyone against the wall then picked him out and shot him in the head.
Some of the informers inside the IRA continued with their republican activities. Some were, indeed committed republicans, who felt they had been compromised by the Army, or police, but still tried to protect IRA operations; in effect, deceiving both sides and trying to maintain their credibility.
A recent article in An Phoblacht, written to discredit one of the biggest-known informers, Sean O'Callaghan, acknowledged that the IRA itself sometimes knew men were informers and preferred not to harm them.
At the end of the Provo campaign, we began to get some idea not just of the degree to which the IRA had been penetrated, but to what level.
The biggest shock was that Freddie Scappaticci, who was on the IRA security team, tasked with catching informers, was working for the British.
The Police Ombudsman is now investigating several killings of alleged informers by the IRA 'nutting squad'.
What other word than collusion better describes a state agent accusing people of informing, extracting confessions from them by torture and then killing them?
This raises the appalling prospect that many of those executed as informers were killed to protect real informers operating at a higher level.
Claims have been made by a former British Army agent that Martin McGuinness was himself an informer with the codename 'J118', though he has emphatically denied this and clearly his former comrades believe him, or he would have had to flee for his life.
But former Provos critical of the peace process routinely rehearse such claims against McGuinness and Adams and close relations on social media.
We do know that the head of administration in Sinn Fein, Denis Donaldson, was a police informer throughout most of the peace process.
He appears to be an example of an agent working for both sides, for he was implicated in gathering intelligence inside Stormont on members of the security forces and the Prison Service, many of whom had to move home after the scale of his spying was unearthed.
At the end of the Troubles, IRA members were afraid to go out on operations, because they didn't trust those they were sent out with not to be informers, or spies.
This massive infiltration of the paramilitaries, combined with a failure to arrest and convict many players, including agents, derived from a type of policing and security response which prioritised intelligence over evidence.
Indeed, evidence was squandered, or destroyed, presumably to protect intelligence channels.
De Silva, who exposed more of this than anyone else, concluded, 'that the intelligence-led security response to the Troubles did play a significant role in constraining all terrorist organisations, to the extent that they were forced to realise their aims were not achievable by violent means.
If that is so, it is a story that should be told.