The Special Criminal Court ruled that it cannot accept the opinion evidence of a Garda chief superintendent that seven Dublin men are IRA members.
It said this was because there was not full disclosure in advance to the defence that telephone intercepts were part of the basis for his opinion.
Det Chief Supt Peter Kirwan, head of security and intelligence at Garda headquarters, previously told the court he believed, on the basis of confidential information, that all seven accused were members of the IRA.
He claimed privilege in relation to the information sources but during cross examination he said it was based on human sources and telephone intercepts.
On Tuesday Mr Justice Paul Butler, presiding at the non-jury court, said this had not been disclosed in advance to the defence and a “basic unfairness of procedure” had resulted and the only remedy was to rule the belief evidence as inadmissible.
Prosecuting counsel Vincent Heneghan applied for an adjournment to allow the prosecution to take instructions from the DPP in relation to the trial and the court adjourned the trial until Friday.
The seven men before the court are: Kevin Braney (40) of Glenshane Crescent, Tallaght ; Des Christie (50) of Liam Mellows Road, Finglas; Hubert Duffy (47) of George’s Place in Dublin 1; William Jackson (55) of Dooncourt, Poppintree; Declan Phelan (33) of Lanndale Lawns, Tallaght; John Brock (42) of Glenview Park, Tallaght, and Darren Murphy (44) of Rory O’Connor House in Dublin 1.
All seven have pleaded not guilty to membership of an illegal organisation styling itself the Irish Republican Army, otherwise Óglaigh na hÉireann, on March 29th 2013.
The prosecution claimed that the seven men were part of an IRA operation to extort money from a used-car dealer in Clondalkin and had travelled to the dealership for that purpose.
The court heard that members of the Emergency Response Unit and the Special Detective Unit moved in to arrest the men and that items were recovered from the scene.
In follow-up searches of two vans, an office and kitchen, gardaí found cable ties, gloves, balaclavas, a baseball bat, lump hammer, pepper spray and a Glock pistol.
The prosecution case relied on garda observations of the men on the morning of their arrest, items found at the scene, their response to questioning during garda interviews and the opinion evidence of Chief Supt Kirwan.