The Ulster Unionist Party's Doug Beattie has said serious consideration must be given to legal action in connection with the Regent's Park bombing following yesterday's High Court ruling on John Downey and the Hyde Park bombing.
It was ruled that Downey was an "active participant" in the Provisional IRA's July 1982 blast and that he was jointly responsible with others for the attack.
The Regent's Park bombing occurred two hours after the Hyde Park attack and killed seven bandsmen of the Royal Green Jackets. No one has been charged in connection with it.
Reacting to yesterday's ruling, former soldier and Military Cross recipient Mr Beattie said it brought a "small degree of justice" to the families of the four members of the Blues and Royals murdered in Hyde Park.
"There was a great deal of dismay in February 2014 when a criminal case against John Downey collapsed because he was in possession of an on-the-run letter," added the UUP's justice spokesperson.
"Today, thanks to the perseverance of the victims' families and their legal team in a civil case, a court of law has found that Downey was an active participant in that IRA bombing and the way is now clear for a damages claim to be made against him."
Kenny Donaldson, from victims' group the South East Fermanagh Foundation, said his group was honoured to have supported the Hyde Park families throughout the process.
"This is a joint victory. This result should and must now inspire innocent victims and survivors of terrorism to pursue justice, truth, accountability and reparations from those who have forever changed their lives through their futile and unjustifiable acts of terrorism," Mr Donaldson added.
TUV leader Jim Allister , meanwhile, said the ruling was a "stark reminder of just how a great travesty the on-the-run letter scheme was".
"Downey should be facing a criminal court, not a civil one," he continued.
"The fact that he is not is a great stain on the United Kingdom and a telling insight into just how perverse the peace process is.
"This is the sort of crime which the powers that be gave out on-the-run letters for in order to advance the process.
"While innocent victims will rightly celebrate this victory, they will doubtlessly also reflect on how those who should have brought Downey to justice have failed them."