The judge hearing the trial of Soldier F, the former British paratrooper charged with two counts of murder on Bloody Sunday, has been hearing legal arguments about the inclusion of a crucial piece of evidence.
It relates to statements of two other soldiers, G and H, which place Soldier F at the scene of the fatal shootings and state that he opened fire.
Soldier F is charged with the murder of 22-year-old Jim Wray and 26-year-old William McKinney in Glenfada Park North in Derry on 30 January 1972.
He's also accused of five counts of attempted murder. He denies all the charges.
The statements of his fellow paratroopers are a key plank of the prosecution case.
The trial has heard that Soldier G is now dead.
Soldier H has indicated that he is not prepared to give evidence in the case invoking his legal right now to incriminate himself.
This morning, the defence argued that as they were being denied the opportunity to test the veracity and accuracy of the statements provided, they should not be introduced as evidence.
The prosecution accepted yesterday that without the statements the remaining available evidence would not be sufficient to sustain a prosecution.
Series of flaws, inconsistencies and lies
Mark Mulholland KC for the defence said there had been a series of flaws, inconsistencies and lies in Soldier's H account of what happened in Glenfada Park North on Bloody Sunday over the years.
He claimed that in some instances he'd provided an account which sought to justify his own firing on the day.
The court heard that Soldier H had fired 22 rounds, more than any other soldier on the day.
His original statement regarding the events of the day - which the prosecution relies on - was enveloped in a "complete cloud of uncertainty".
"There is no ability for us in this case to properly test and assess the reliability of the material," Mr Mulholland said.
At the opening of the proceedings the trial judge Mr Patrick Lynch raised the issue of a social media post by a loyalist blogger which had called into question the integrity of the trial.
Judge Lynch said the blogger was fortunate that the case was being heard by him only in the absence of a jury under the so-called Diplock system.
He said had a jury been sworn the case might have had to have been aborted, the prosecution restarted and the loyalist investigated under contempt of court legislation.
He said the blogger's views were a "matter of total indifference" to him and he'd decided not to report the matter to Northern Ireland's Attorney General.
However, he said, if she took a different view of the development "that will be a matter for her".
The legal argument is expected to continue tomorrow with a reserved judgement being delivered next Wednesday.
