Their silence is deafening. Can you imagine the pitch of self-righteous frenzy that unionist politicians would by now have reached had it been revealed that the main source of the IRA's weapons in the early days of the Troubles had been the Irish army?
That innocent Protestant civilians had been gunned down in the streets by terrorists using those weapons? That elements of the Garda were close to the IRA and were giving information to Gerry Adams? That the Irish government knew, and suppressed the information?
Yes, you can imagine it. The silence which has greeted the revelations carried in The Irish News this week about collusion between the security forces and loyalist paramilitaries is perhaps the most shameful aspect of the whole sordid story.
As I write, unionist politicians have responded minimally and only to try to deny that the information is true and accurate.
Lord Denning infamously said that the prospect that the Birmingham Six might be innocent presented such an "appalling vista" that it must be rejected. This is another appalling vista and it must be faced.
The sources of the documents published in this paper this week, and painstakingly analysed by Steven McCaffery, simply cannot be plausibly rubbished. This is evidence from the heart of the British establishment.
It was uncovered by researchers at the Pat Finucane Centre and Justice for the Forgotten.
The Irish News has published documents which show that in 1973 British military intelligence knew that up to 15% of UDR soldiers were also involved with loyalist paramilitary groups. That the UDR was the "best single source of weapons" for those groups. That the weapons were being used in sectarian murder attacks on catholic civilians. That in 1975 Labour secretary of state Merlyn Reese briefed Tory leader Margaret Thatcher that there were elements in the RUC who were "very close" to the UVF, and were prepared "to hand over information, for example, to Mr Paisley".
This reference to the DUP leader is particularly interesting in the light of the false allegations he has made in the House of Commons regarding those he claims were responsible for the Kingsmills Massacre.
Paisley claimed his information came from security sources but the RUC denied and repudiated it.
Much of the so-called information passed to loyalists over the years was based on rumour, fuelled by passionate sectarianism. Many innocent people have died as a result.
The UDR was formed out of the notorious B Specials and brazenly carried on the tradition of that unionist militia. Remember that dual membership of the UDR and the UDA was for a considerable time perfectly legal. The 'Subversion in the UDR' document reveals that the main anxiety on the part of the British was that the loyalty of a large element of the UDR was to Ulster and not to Britain, and the implications of that.
Although loyalist paramilitaries boasted that they were the "gloves off" branch of the security forces, allegations about collusion have always been met with denial from 'respectable' unionists. Far from accepting that it was institutionalised in the local security forces, unionists have even rejected the idea that there were "bad apples".
The UUP's former security spokesman, Ken, now Lord, Maginnis, claimed that in his time in the UDR (during the 1970s) he had only come across a small number of "bruised" apples.
This is hardly in keeping with the comment in the 1973 British intelligence report that if you removed the undesirables you would be left with a "very small regiment indeed".
John Stalker tried to investigate collusion and was thwarted.
John Stevens was obstructed over 14 years but found that it existed during the 1980s, including "the extreme of agents being involved in murder".
Mr Justice Henry Barron's investigation into the Dublin and Monaghan bombs revealed a chilling network of loyalists, policemen and UDR soldiers who murdered with apparent impunity while the British and Irish authorities were preoccupied with the "real" enemy, the IRA.
Barron was refused access to British intelligence documents he needed.
Judge Peter Cory protested vehemently when the British rushed through legislation making it impossible for the sort of inquiry he had called for to be carried out into the murder of Pat Finucane. The Saville Inquiry was obstructed and evidence willfully destroyed.
A Tyrone coroner was refused access to documents he needed to carry out inquests into controversial murders in the 1990s.
We now know a bit more about what they have got to hide.