Self-confessed IRA man Michael Hayes may have "important evidence" about the Birmingham pub bombings, a British High Court hearing has been told.
Ten of the victims' families were at the High Court in Birmingham yesterday in a legal bid to overturn coroner Sir Peter Thornton QC's ruling banning the identification of suspects at fresh inquests.
The relatives are asking for a judicial review of that decision, in order to widen the inquests' scope and include "the perpetrator issue".
In opening submissions, their barrister Adam Straw said: "There's been no full and independent investigation for who was responsible."
If the coroner's ruling was overturned, Mr Straw said it could open the door to individuals like self-confessed IRA man Michael Hayes being asked to give evidence at the inquests.
Dublin-based Hayes previously told a BBC interview he took "collective responsibility" for the organisation's activities in England, including the pub bombings.
He also claimed to have defused a third bomb placed outside Barclays Bank on the city's Hagley Road, when the scale of the bloodshed became clear.
Speaking in July, when asked if he had planted either bomb in the Tavern in the Town or the Mulberry Bush, he replied: "No comment. No comment."
Mr Straw told the judges: "Michael Hayes may be put on the stand and may bring forward important evidence."
Asked about the fairness of "naming" such individuals, Mr Straw said: "The names of the Birmingham Six and five other individuals are already out there. One only has to do a simple Google search."
However, Sir Peter's barrister said that inquests were not the correct arena to consider who carried out the bombings, and risked turning forthcoming hearings into a "proxy criminal trial".
In written submissions for the coroner, his barrister Peter Skelton QC concluded: "Thus the many years of expensive and exhaustive endeavour would not result in the claimants' principal goal: a public conclusion about who bombed Birmingham.
"That aim is entirely legitimate and understandable. But it is not one that these inquests can achieve."
The city centre double bombings, widely believed to be the work of the IRA, killed 21 people and injured 182, making it - at the time - the deadliest peacetime attack on the UK.
Six men, known as the Birmingham Six, were imprisoned for the murders and served 17 years behind bars in one of Britain's most infamous miscarriages of justice, before their convictions were quashed.
The High Court hearing is the latest stage in a lengthy campaign by the families for "truth and justice".
Senior coroner Louise Hunt last year allowed new inquests after hearing evidence the British state may have been protecting a British government informant, and that the British police allegedly ignored two tip-offs of an imminent IRA attack.
In submissions to Lord Justice Simon and Mrs Justice Carr, Mr Straw said: "There's compelling interest for a full investigation for who was responsible with the aim of bringing them to justice."
The barrister added: "In our submission, at the end of the inquest, the coroner could perfectly properly say if one or more of the individuals unlawfully killed the victims."
Lord Justice Simon replied: "Or possibly none."
New inquests are on hold until the High Court judges deliver their ruling.
Some of the bereaved families said they would "no longer participate" in the inquests, without the perpetrator issue being included.
The hearing continues tomorrow.