art 27 Evidence
(1) The Tribunal may receive in evidence any document or information notwithstanding that such document or information would be inadmissible in a court of law. (2) No person shall be compelled to give any evidence or produce any document which he could not be compelled to give or produce on the trial of an action in a court of law in that part of the United Kingdom where the appeal is to be determined. (3) The Tribunal may require oral evidence of a witness (including a party) to be given on oath or affirmation and for that purpose the president or the proper officer shall have the power to administer oaths or take affirmations.