Gerry Adams has denied withholding information about child sex abuse claims involving his niece to save his political career.
The trial of his younger brother heard that the Sinn Fein president did not tell police until nine years after Liam Adams had allegedly confessed to abusing his own daughter as they walked together in Dundalk in 2000.
During cross examination at Belfast Crown Court defence barrister Eilis McDermott QC asked why Gerry Adams had not told detectives about the alleged admission until a month before a television programme relating to the child abuse claims was to be aired.
'I am suggesting that the reason you made this statement was to save your political skin,' said Ms McDermott.
Gerry Adams replied: 'If I had been interested in saving my political skin I would not have got involved with the process at the beginning. I tried to fulfil my responsibility as an uncle to a young woman I am very fond of.
'This is above politics and saving my political skin had no consideration in any of these matters.'
The court heard that Mr Adams, on the advice of his solicitor, made two separate statements to police in 2007 and 2009.
'The statement came in two parts - two months and four months apart - and just one month before you were interviewed by a television journalist,' said Ms McDermott.
Mr Adams answered: 'That may be chronologically right but to link one to the other is absolutely and totally wrong.'
Earlier Gerry Adams told the court that his sibling admitted sexually abusing his daughter, Aine.
The Sinn Fein president said that Liam Adams made the alleged admission during a meeting in Dundalk in 2000.
'I had a long walk with Liam. We had a number of conversations.
'During the course of that he acknowledged that he had sexually abused Aine. He said it only happened the once,' Gerry Adams told Belfast Crown Court.
When asked to describe his brother's demeanour for the jury of six men and six women, Gerry Adams replied: 'He was very upset. I remember it was raining.'
Liam Adams, 57, from Bearnagh Drive in west Belfast, denies 10 charges of child sex abuse including rape, indecent assault and gross indecency against his daughter between 1977 and 1983 when she was aged between four to nine years old.
Aine Adams, 40, has waived her right to anonymity.
Gerry Adams was sworn in as a prosecution witness this morning.
Ciaran Murphy QC, counsel for the prosecution, asked Mr Adams to outline the language his brother used when he made the alleged admission.
He said: 'To the best of my recollection the terms that he used were that he had molested her or that he had interfered with her, that he had sexually assaulted her.'
Mr Adams said he had first confronted his brother about the alleged abuse during a meeting in Buncrana, Co Donegal in 1987.
Mr Adams at Laganside Courts in Belfast today. Gerry Adams is appearing in Belfast Crown Court at the trial of his brother Liam Adams. Liam Adams denies ten charges of sexually abusing his eldest daughter, Aine, more than 30 years ago
Liam Adams, right, is accused of 10 counts of sex abuse against his daughter Aine, left. He denies the charges
He told the court at that time Liam Adams denied the allegations.
He also denied that he had threatened to hit his brother with a hammer if the allegations were true.
'No I did not,' Gerry Adams said.
Later, defence barrister Eilis McDermott QC suggested that the alleged admission had not taken place.
'You say that your brother made an admission to you in 2000 walking in the rain in Dundalk. I should make it clear to you that I suggest no such admission was made.'
Gerry Adams replied: 'I don't accept that but I understand it.'
When the allegations first emerged, he was MP for West Belfast.
Earlier the trial heard how Liam Adams had worked at a number of youth clubs in the heartland of his brother's former constituency - Clonard Youth Club for five years from 1998 and another club in the Beechmount area known as the Blackie Centre from about 2004.
He also worked with young people aged in their mid to late teens in Dundalk - which is in his brother's current constituency of Louth - for about a year from 2003.
Liam Adams had passed police checks, it was claimed in court.
Gerry Adams said he had told a priest about the sex abuse allegations when he became aware that his brother was working with children at Clonard but had not gone to the police.
'At this point Aine was an adult. This was a legacy issue. I am not Aine's parent. I am an uncle and she has many uncles. I was trying my best to resolve these matters in a way which helped Aine but also in a way which helped Liam to get rid of his demons,' he said.
Ms McDermott suggested that it was his duty as an MP to inform the civil authorities.
'You have a duty to inform the police if you thought your brother posed a danger,' she said.
Mr Adams replied: 'I did not believe that my brother was a danger. Given his acknowledgement to me and the fact that he said this only happened the once. I have had lengthy conversations with my brother and I think I knew him very well.'
Gerry Adams said he only engaged with the police after Aine went to the PSNI in 2006.The trial continues.