Michael McKevitt, who was yesterday convicted of directing the activities of an illegal organisation, has been sentenced to 20 years in prison.
The Special Criminal Court had also found him guilty of membership of the Real IRA.
The three judges at the Special Criminal Court said they had contemplated sentencing McKevitt to 25 years in jail.
However, they said they took into account the fact that he had a family, had no previous convictions, is aged 53, and that he must be afforded an opportunity to rehabilitate himself.
Mr Justice Richard Johnson said that the court was satisfied the offences were planned and pre-meditated to cause serious harm to people and property.
He said the court was also satisfied that McKevitt had a leading role in directing the Real IRA and had induced others to join and commit offences.
McKevitt was told by a prison officer that the judges said if he wished to appeal he had to come in to the court room to make the application in person.
He refused to attend while the judges passed sentence, but did come up into the dock afterwards to apply for legal aid and for leave to appeal.
Leave to appeal was refused.
