A brother of one of those shot dead on Bloody Sunday has secured High Court permission to challenge the decision to drop murder charges against a British army veteran.
Michael McKinney was granted leave to seek a judicial review of the Public Prosecution Service's determination that Soldier F should not stand trial.
With the case advancing to a full hearing, committal proceedings against the ex-paratrooper are now expected to be put on hold until September.
Thirteen people were killed when members of the Parachute Regiment opened fire on civil rights demonstrators in Derry on January 30, 1972. Another of those wounded on the day died later.
Soldier F was charged with the murders of William McKinney and James Wray, plus five counts of attempted murder, over the shootings.
Last week, however, Northern Ireland's Public Prosecution Service (PPS) announced that he will not now stand trial.
The case against him was reviewed after the trial of two other military veterans for Troubles-era offences collapsed in Belfast earlier this year.
Based on an assessment of the admissibility of evidence, it was concluded that the test for prosecution was no longer met.
Relatives of five of the Bloody Sunday victims are already seeking to judicially review the PPS for not charging former soldiers with their murders.
Their case is listed for a five-day hearing in September, and the court was told the separate challenges overlap.
Tony McGleenan QC, for the PPS, accepted Mr McKinney has an arguable case on two grounds centred on the admissibility of historical statements.
Following that concession, Mrs Justice Keegan, sitting with Mr Justice Horner, ruled that the legal test had been met.
"We will therefore grant leave (to apply for judicial review) on those two grounds," she confirmed.
"We stress that those two grounds must have priority in terms of hearing time and adjudication."
Mr McKinney, who followed proceedings remotely from a community centre in Derry, said his family was delighted with the outcome.
"The PPS should not have contemplated discharging Soldier F in circumstances where the High Court is already actively considering the decision making surrounding decisions not to prosecute F for his involvement in two further murders," he insisted.
"The position it adopted was a source of great distress to our family. This represents a victory today for us and Jim Wray’s family and those wounded by Soldier F."
Criminal proceedings against the former paratrooper were set to be discontinued at Derry Magistrates' Court on Friday.
Lawyers for Mr McKinney had initially sought an order to prevent the formal ending of murder charges the military veteran faced.
But due to the legal developments, the PPS will instead now request an adjournment.
During the hearing Mr McGleenan acknowledged: "The grant of leave has altered the position quite significantly.
"The PPS will appear tomorrow before (Derry Magistrates' Court) and make an application for an adjournment of the committal proceedings until September."
Counsel for Soldier F argued there is now a statutory obligation to discharge his client following the evidential assessment.
However, Mark Mulholland QC added: "Bearing in mind the strictures and that it is to be revisited in a very short timeframe, then I would not be seeking to oppose the adjournment application tomorrow."
Before rising, Mrs Justice Keegan recognised the competing interests in the case.
She said: "The court is trying to grapple with these difficult issues and not change the situation until we at least get to the evidence and see where we are in September."
Outside court Mr McKinney's solicitor, Fearghal Shiels of Madden & Finucane, confirmed full arguments will be made at the five-day main hearing.
He added: "That case will examine a decision not to prosecute another soldier for the murder of William McKinney, Jim Wray and the attempted murder of four others, and other decisions which we contend are flawed which have, to date, resulted in other indentifiable paratroopers escaping justice."