Jonathan Dowdall will be allowed to testify against Gerry Hutch at his murder trial.
The former Sinn Féin councillor was also due to stand trial for the murder of David Byrne at the Regency Hotel in Dublin but the charge against him was dropped.
The defence claimed that was done in exchange for him giving evidence against Gerry Hutch.
The prosecution denied that was the case and the judges have refused the defence application, paving the way for Jonathan Dowdall to give his evidence.
