BBC News NI Crime & Justice Correspondent
The defamation case filed by Gerry Adams against the BBC was scheduled to begin on Tuesday in the High Court in Dublin.
The former Sinn Féin president believes he was slandered in a 2016 plan, claiming that he approved the murder of whistleblower Denis Donaldson was wrong.
Donaldson was shot dead in Donegal for 20 years after admitting he was a policeman and MI5 agent.
Mr. Adams, 76, denied any involvement.
In 2009, the real IRA admitted to killing Donaldson who worked for Sinn Féin.
Mr. Adams also claimed that he had broadcast poems in BBC Online articles based on broadcasting (BBC NI Spotlight TV documentary) which contained claims from anonymous sources.
He is seeking damages, accusing his reputation of damage.
The case is expected to last for several weeks and will be heard before a jury.
During the pre-trial hearing, the BBC argued that the broadcasts and publications were published in good faith and focused on the public interest.
It noted that due to careful investigation, reports constituted responsible journalism.
Mr. Adams served as former president of Republican Sinn Féin from 1983 to 2018.
Until 2011, he served as TD (TD) in Dail (Parliament of Ireland) between 2011 and 2020.
Mr. Adams led the delegation of Sinn Fein in peace negotiations and finally ended the trouble after the Good Friday Agreement signed in 1998.
He was detained in the early 1970s when the Northern Ireland government was not tried for suspected quasi-military participants.
Mr. Adams has been denied being a member of the IRA.
Mr Donaldson was once a key figure in Northern Ireland's political power, but he was brutally murdered in 2006 after appearing as a spy.
In the 1970s, he was interned without trial.
After signing the Good Friday Agreement, Sinn Féin appointed Mr. Donaldson as the principal executive of the party's Stormont office.
In 2005, Mr. Donaldson admitted that he was a spy in British intelligence for twenty years and then disappeared from Belfast.
He was found dead in a small cottage in Grentals, County Donegal.