31.—(1) If in proceedings on a complaint under Article 28 either the complainant or the respondent claims that the respondent was induced to act in the manner complained of by pressure which a trade union or other person exercised on him by calling, organising, procuring or financing a strike or other industrial action, or by threatening to do so, the complainant or the respondent may request the industrial tribunal to direct that the person who he claims exercised the pressure be joined as a party to the proceedings.
(2) The request shall be granted if it is made before the hearing of the complaint begins, but may be refused if it is made after that time; and no such request may be made after the tribunal has made its decision as to whether the complaint is well-founded.
(3) Where a person has been so joined as a party to the proceedings and the tribunal—
(a)finds that the complaint is well-founded,
(b)makes an award of compensation, and
(c)also finds that the claim in paragraph (1) is well-founded,
it may order that the compensation shall be paid by the person joined instead of by the respondent, or partly by that person and partly by the respondent, as the tribunal may consider just and equitable in the circumstances.
(4) Where by virtue of Article 30 there is more than one respondent, the above provisions apply to either or both of them.