A body that exercises jurisdiction over the internal affairs of a particular profession or association under powers conferred either by statute (e.g. the disciplinary committee of the Law Society) or by contract between the members (e.g. the disciplinary committee of a trade union). The decisions of these tribunals are subject to judicial control under the doctrine of * ultra vires and, if they are statutory, when there is an error of law on the face of the record. Compare administrative tribunal.