The state was involved in mass murder on British soil, a lawyer has told a coroner's court.
The security forces colluded with loyalist paramilitaries in 80 deaths between July 1972 and June 1978 in Northern Ireland's "murder triangle" in counties Armagh and Tyrone, Leslie Thomas QC said.
He said many were carried out by the Glenanne Gang of gunmen with the alleged involvement of soldiers and police officers.
Mr Thomas said it could take a year to hear inquests and compared the task to that of investigating the Hillsborough football disaster.
"If what we say is right this is the biggest involvement of state agents in mass murder on British soil," he said.
He added: "We say that what the families of the bereaved want, quite simply can be put in a few words: they want the truth, they want the truth to come out, they want justice."
Mr Thomas was addressing a preliminary hearing in Belfast of two inquests involving a Ulster Volunteer Force (UVF) bombing at the Step Inn in Keady in Co Armagh in 1976 during which Catholics Elizabeth McDonald, 38, and Gerard McGleenan, 22, died.
He said the same weapons were used in many of the Glenanne murders and the killers adopted the same modus operandi, accused the authorities of state-sponsored terrorism and claimed one individual involved in killing Ms McDonald should have been dealt with sooner.
He said: "The murder of Betty McDonald could have been avoided, could have been avoided had that individual been taken off the street earlier on or the weapons been taken off the street earlier on, or there had not been the collusion amongst state agents in covering up earlier murders then in terms of Betty McDonald's right to life we say she may be still here today, living long into life with her husband."
The UVF gang operated out of farms in Armagh and Tyrone in the mid 1970s when the Troubles were at their worst.
Lawyers for the victims have insisted only a public inquiry or an inquest covering all the deaths can get to the truth of the collusion claims. Senior coroner John Leckey said he was constrained by the resources available to his office.
The Police Service of Northern Ireland's (PSNI) Historical Enquiries Team (HET) has found "indisputable evidence" of security force collusion in the group.
Northern Ireland Secretary Theresa Villiers has declined to be represented at the inquest. No submission has been made to her seeking a public inquiry but Mr Thomas said the McDonald family was not surprised she allegedly did not want to be involved.
He added: "This is the biggest case of state collusion in mass murder of innocent individuals. This is a state murdering its own, you cannot get bigger than that, and therefore while one sees and understands and looks at what is happening in Hillsborough, if what we say has occurred on, lets face it, British soil, why should that not be investigated?
"British security agents being involved in deaths of British citizens, it does not get worse than that."
Mother-of-three Ms McDonald and Gaelic Athletic Association (GAA) footballer Mr McGleenan were killed when a no-warning loyalist bomb detonated outside the Step Inn pub and nearby houses in August 1976. Twenty-five other people were injured.
Northern Ireland's Attorney General John Larkin QC ordered the new inquest.
Mr Thomas acknowledged there had been convictions in some of the other killings he said were linked, but he added a narrow criminal investigation was not enough.
He said across the cases there had been a repetition of similar failings by the investigating authorities, a lack of criminal convictions, the killings happened in close proximity to each other, and created similar victims while pursuing similar modus operandi.
He added the deaths involved a similar group of individuals involved in a number of attacks.
"Many of those responsible were either serving or former members of the security forces. There were close ballistic links between the victims, the weapons used in many of the killings which originated within the Ulster Defence Regiment (a branch of the army recruited in Northern Ireland)."
He quoted the HET report: "Despite the obvious pattern and linkages between these offences, only cursory efforts have been made to investigate further.
"No determined efforts were made to investigate them in a meaningful fashion.
"This (Step Inn) bombing could have been prevented and should have been detected."
Mr Thomas said precedents for a linked series of inquests were given by that into the deaths of Russian agent Alexander Litvinenko and Azelle Rodney, who was allegedly shot dead by Met Police.
He told Mr Leckey: "I can connect and join the dots in relation to various individuals who were named here to various atrocities, various bombings, various shootings, various matters and I can make the link on various weapons, various ballistics.
"This document enables me to tie up individuals."