John Gilligan has been convicted of the offence of having a mobile phone in his prison cell in Portlaoise three years ago.
The convicted drug dealer was charged after Prison Officers searched his cell in July 2008 and found a mobile phone, a SIM card, a charger, two pairs of ladies underwear and tablets.
The 59-year-old tried to suggest that the phone had been planted in his cell but Judge Gerard Haughton ruled today that there was no evidence of this.
Gilligan was sentenced to eight months in prison additional to the 22 years he is already serving.
It is the second time he has been convicted of a crime while in Portlaoise Prison.
Gilligan smiled and mockingly wiped his brow during the proceedings.
He has appeared in Portlaoise District Court 48 times to deal with this charge.
In addition he also appealed to the High Court to try and halt the prosecution but was unsuccessful.
During the course of the proceedings a mobile phone was also found in a bag which Gilligan brought to court.
A file on this has been sent to the DPP.
