The rail signalling inquiry was suspended indefinitely yesterday, following a High Court order on Friday which imposed restrictions on Oireachtas investigations.
The hearings were within a day of completion, but the inquiry's chairman, Mr Seβn Doherty TD, said the ruling meant their report might never be written.
As the inquiry rose, he attacked the order by Mr Justice Kelly, Mr Justice Morris and Ms Justice Carroll which barred Oireachtas inquiries from making findings of fact in relation to people who were not members of the Oireachtas.
The issue now for the subcommittee "was the extent to which the Oireachtas can be permitted to exercise its legislative function".
The order followed a challenge by members of the Garda Emergency Response Unit to a separate Oireachtas inquiry into the death of Mr John Carthy.
Mr Doherty claimed the ruling employed a "narrow and limiting view" of the role of parliament in a judgment. He said: "The courts have reserved to themselves an organic view of their powers. I confess that I do not understand why the Constitution appears to mean one thing in Kildare Street and another in Inns Quay."
In 24 public sessions the subcommittee inquired into a £36 million overshoot on an Iarnr≤d ╔ireann signalling system and Esat's construction of a telecoms network on the railway, breaching CI╔'s procurement policy.
