Independent TD Maureen O'Sullivan has defended writing a letter in defence of a man who was jailed yesterday for being a member of a dissident republican organisation.

Speaking on RTÉ's Morning Ireland, she said she could stand over the letter because it was written in the context of an application for bail and because she knew the man.

Donal Ó Coisdealbha, 25, from Abbeyfield, Killester in Dublin pleaded guilty to membership of an unlawful organisation styling itself the Irish Republican Army, otherwise Óglaigh na hÉireann otherwise the IRA within the State on 13 May 2015.

He was sentenced to five-and-half years in prison after being arrested on explosive charges in the lead up to the visit of Prince Charles last year.

Ms O'Sullivan said that it was the type of letter that she would have written about other young people who had gotten in trouble in the law, and she would state in these letters things that she could stand over.

She said the letter was written to highlight that people were being left on remand for long periods of time, and Ó Coisdealbha had been in jail for over a year at the time she wrote the letter.

She added that when she wrote the letter, she was unaware that he would plead guilty.

The TD for Dublin Central said she was not aware that the letter would be used when Ó Coisdealbha was sentenced, and that it was disturbing that her letter was being taken as an endorsement of violence and physical force.

She stressed that she has always been totally opposed to the use of violence.

When questioned about comments Ms Justice Isobel Kennedy made about her yesterday, Ms O’Sullivan said the judge had taken a major leap in her summarising and "put two and two together and come up with 440, and not four".

Ms Justice Kennedy described as "puzzling" the letter written by Ms O’Sullivan.

Ms Justice Kennedy said the court was concerned that Ms O'Sullivan expressed concern about the accused's situation on remand but not about his activities which the court found "regrettable."

She also noted that Ms O'Sullivan may have been unaware of his intention to plead guilty but the testimonial "does not address his acceptance of guilt".

The Special Criminal Court sentenced Ó Coisdealbha to seven years in prison with one-and-a-half years suspended.