142. (1) The court shall be entitled of its own volition, at any time during the trial of a petition, to direct that a particular person shall be brought before the court and shall give evidence at the trial, and where the court so directs the cost of bringing the person before the court (including any moneys payable to the person as witness’s expenses) shall be regarded as part of the costs of the petition.

(2) Subject to paragraph (3), a person who is called as a witness at the trial of a petition shall not be excused from answering any question relating to any offence at or connected with the relevant European election on the ground that the answer thereto may incriminate or tend to incriminate that person or on grounds of privilege: provided that—

(a) a witness who satisfies the court that he or she has answered truly all the questions which the witness is required by the court to answer shall be entitled to receive from the court a certificate stating that the witness has so answered, and

(b) an answer by a witness who has received such a certificate to a question put at the trial of a petition shall not, except in the case of any criminal proceeding for perjury in respect of the evidence, be in any proceeding, civil or criminal, admissible in evidence against the witness.

(3) Nothing in this rule shall be construed as affecting the right of any party to a petition to call any person as a witness.