State witness Jonathan Dowdall has lost his appeal of his four-year sentence for facilitating the Regency Hotel murder of David Byrne.

Dowdall, whose sensational evidence in the murder trial of Gerry ‘The Monk’ Hutch was ultimately rejected, hoped that his sentence for facilitating the now infamous killing could have been reduced, arguing that it was too severe.

However the three judges of the Court of Appeal ruled on Friday that if anything Dowdall’s four year sentence was “very lenient” and if they had any doubts as to the appropriateness of that sentence “it would be as to whether a more severe sentence ought to have been imposed.”

READ MORE: Jonathan Dowdall compared to Bart Simpson during dramatic closing speech at Gerry Hutch trial

Mr Justice George Birmingham told the court that the judges “will content ourselves by saying we are entirely satisfied that the sentence cannot be regarded as unduly severe. “We therefore dismiss the appeal,” he said.

Dowdall, with greying hair and dressed in all black, remained stony faced as the ruling was read out - while gardai and prison officers flanked him in the courtroom.

An armed garda presence also stood watch outside the Criminal Courts of Justice as Dowdall - who continues to remain under threat, was escorted to and from prison on Friday.

The former Sinn Fein councillor, who is awaiting word on his application for the Witness Protection Programme, now remains in an isolated landing in Limerick Prison.

Dowdall argued in his now failed appeal that he was “duped” and put in the “firing line” for the Regency Hotel attack that saw Kinahan cartel associate David Byrne murdered by the Hutch gang.

His barrister Michael O’Higgins SC had argued before the three judges that while the State may say that the hotel room that was booked by Dowdall was part of the "launching pad" for the murder of Mr Byrne, he would submit it was the "launching pad for a contrived event plan of disinformation, which was put together in a way where my client was left front and centre".