"4 Power to require further particulars and attendance of witnesses and to grant discovery … (2) A tribunal may, on the application of a party made either by notice to the Secretary or at the hearing of the originating application, or of its own motion- (a) require the attendance of any person, including a party, as a witness, wherever such person may be within Great Britain, and (b) if it does so require the attendance of a person require him to produce any document relating to the matter to be determined, and may appoint the time and place at which the person is to attend …"
"(1) The tribunal shall, so far as it appears to it appropriate, seek to avoid formality in its proceedings and shall not be bound by any enactment or rule of law relating to the admissibility of evidence in proceedings before the courts of law. The tribunal shall make such enquiries of persons appearing before it and witnesses as it consider appropriate and shall otherwise conduct the hearing in such manner as it considers most appropriate for the clarification of the issues before it and generally to the just handling of the proceedings."