The BBC will claim that Gerry Adams was allegedly a leading member of the IRA and on its Army Council as part of its defence against defamation proceedings brought by the former Sinn Féin leader, the High Court has heard.
The broadcaster will also argue in its defence that Mr Adams was allegedly a leading member of the IRA during its campaign of violence throughout the Troubles and had a history of not condemning the killing of informers.
Mr Adams claims the BBC defamed him when it broadcast allegations in a '2016 Spotlight' programme that he had sanctioned and approved the killing of former SF official and double agent Denis Donaldson in 2006 who also worked for decades as a spy for the British.
There was also a follow-up article on the BBC website which contained the same defamatory allegations, he says.
The allegations complained of were made by anonymous source, referred to as "Martin" in the programme.
Mr Adams has at all times denied having any involvement in Mr Donaldson's death, which in 2009 was claimed by dissident republicans.
He also says that all allegations made against him in connection with the death, or that the IRA had any involvement in the killing were attempts to discredit republicans.
The BBC denies defamation and claims the programme/publication was put out in good faith and during discussion on a subject of public and vital interest.
It constituted responsible journalism, which was the result of careful investigation, it argues.
In its pretrial motion the BBC seeks discovery from Mr Adams of materials and documents it claims are relevant to its defence.
The material sought by the BBC includes any documents or evidence he has in his possession regarding his alleged relationship with the IRA, knowledge of the IRA's treatment of informers and comments he allegedly made in a 1987 press conference that "Everyone in West Belfast knows that the consequence of informing is death."
Through his lawyers Mr Adams opposes that application and says the motion should be dismissed.
The High Court heard on Wednesday that the broadcaster has pleaded as part of its defence that Mr Adams was allegedly a leading member of the IRA during its campaign of violence throughout the Troubles and a member of its Army Council.
Eoin McCullough SC for the BBC said the documentation sought is relevant to its defence, that the matters it published, and broadcast were fair, reasonable and in the public interest.
Counsel added that the materials have been sought to help his client prove that Mr Adams’ 'public persona' is such that the 2016 BBC article and broadcast did not damage his reputation.
Tom Hogan SC, instructed by Johnson Solicitors for Mr Adams said the material sought was vague and irrelevant in relation to what has been pleaded before the court.
He said the BBC's motion was "a fishing expedition" and an attempt to trawl through a large volume of material amassed by Mr Adams during his long political career.
There was a "complete disconnect" between what was being sought in discovery and what had been published, counsel said.
Counsel said that the BBC's application was somewhat extraordinary given that it does not plead in its defence that the allegations complained of are the truth.
It was, counsel added, an attempt to justify the alleged defamation.
In a separate pretrial motion Mr Adams has asked the High Court to strike out certain aspects of the BBC's defence against his defamation action stuck out.
The BBC opposes that motion.
Following the conclusion of submissions on both motions Ms Justice Emily Egan reserved her decision.
The judge did not say when she would be able to deliver her judgment.