Jonathan Dowdall's barrister claims his client was "duped" into assisting the criminal organisation behind the 2016 gangland attack at the Regency Hotel.
The former Sinn Féin Councillor was jailed for his role in booking a room at the hotel for the gang, but he is trying to have his sentence set aside.
While testifying against Gerry ‘The Monk’ Hutch at his trial for the murder of David Byrne, Jonathan Dowdall told the judges that he and his father booked a room at the Regency Hotel at the request of Gerry's brother, Patsy.
The room was later used by one of the gunmen who stormed the boxing event that led to Mr Byrne being shot dead.
In his evidence, Dowdall also claimed they later handed the keycard over to Gerry Hutch, who has since been acquitted of murder.
Dowdall was jailed for four years but claims his sentence should be set aside; arguing not enough weight was given to mitigating factors, including his guilty plea and the effect his decision to turn State witness will have on his life.
Sean Gillane, for the DPP, described his sentence as “generous” and “undoubtedly fair.”
Dowdall, who appeared in court under heavy guard, will have to wait until a later date to find out if he has won his appeal.