The BBC opened its defense in a libel case filed by Gerry Adams, who claimed he was defamated on the radio and articles, which claimed he approved the murder of British agents.

Eoin McCullough SC, who is acting for broadcasters, told the Dublin High Court that the allegation has been "completely investigated".

He also said it is "irresponsible" to ignore information.

Mr. Adams denied being involved in the 2006 killing of Denis Donaldson - his police and MI5 inside Sinn Féin had spyed for MI5.

Spotlight's 2016 plan includes an anonymous source named Martin, who requested Mr. Adams.

Martin is described as a whistleblower within the IRA.

McCullough said of the 12-person jury that the program provided multiple sources for Martin’s central claims.

“Martin gave her (Reporter Jennifer O’Leary) information, which was irresponsible.

"She not only brought him to the face value. The allegations he made were thoroughly investigated," McCullough said.

He said the BBC is defending the case with two main reasons - it questioned Mr. Adams' claim on the meaning of the story and, in the public interest, it was a "fair and reasonable" publication.

He also said Mr. Adams is entitled to damages because of his reputation as an IRA leader until 2005 - Mr. Adams refused.

"This article and the broadcast do not mean that Mr. Adams approved and approved the murder," McCullov said.

“You’ll see the BBC report that Martin made the allegation, but it clearly shows that it’s an allegation, which clearly shows that Mr Adams said it was nonsense.”

He also explained the idea behind the “very simple” of fair publications.

“As long as the material is in the public interest and he or she does it honestly, he or she has the right to publish the material.”

He said “very careful” is centered around collecting responses to the allegations, and the editorial process has been “hard.”

It is crucial that Mr. Adams suggests that the story is based on an anonymous source, he said.

Mr McCullough said that among the BBC's witnesses, an expert will point out that if Mr Adams complained to the broadcasting regulator Ofcom, it would not be successful.

The lawyer then called Ms. O'Leary to testify - she was a reporter for the Spotlight Project.

Ms. O'Leary started her evidence, and she has been a BBC journalist since 2011.

She said she was not hostile to former President Sinn Féin: “I have no agenda against Gerry Adams.

"You're just making a story. Whose relationship is this."

Earlier, the jury played videos of news excerpts from the 1990s, indicating Mr. Adams was involved in the Northern Ireland peace process.

This is made up of his legal team.

Lasting for 14 minutes, it showed Mr. Adams' meeting, including former U.S. President Clinton and former South African President Nelson Mandela.

It ended with a handshake between Mr. Adams and then Prince Charles in 2015.

Justice Alexander Owens told the jury that this was an example of Mr. Adams' attorney "good publicity" and "maybe a little likable."

Mr. Adams' reputation has become a central feature of the case.

The court was also told that the centre's spotlight was planned to air in September 2016, with a 15,800 audience in Ireland.

The accompanying online story had about 750 hits in Ireland between 2016 and 2017.

The case is now in its third week.

Mr Donaldson was once a key figure in Northern Ireland's political power, but he was murdered in 2006 after he was a spy.

In the 1970s, he was interned without trial.

After signing the Good Friday Agreement, Sinn Féin appointed Mr. Donaldson as the principal administrator 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.

Mr. Adams served as president of the Republican Sinn Féin from 1983 to 2018.

From 1983 to 1992, he served as a member of Parliament in his native Belfast West, from 1997 to 2011, and then as TD (Teachta Dála) in Irish Parlia 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.