77.—(1) If in proceedings on a complaint under Article 74—
(a)the complaint is made on the ground that[F2 the complainant has been subjected to detriment by an act or failure by his employer taking place] for[F3 the sole or main purpose] of compelling him to be or become a member of any trade union or of a particular trade union or of one of a number of particular trade unions, and
(b)either the complainant or the employer claims in proceedings before the tribunal that the employer was induced to[F2 act or fail to act in the way] 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 employer may request the 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 a declaration that the complaint is well-founded.
(3) Where a person has been so joined as a party to proceedings and the tribunal—
(a)makes an award of compensation, and
(b)finds that the claim mentioned in paragraph (1)(b) is well-founded,
it may order that the compensation shall be paid by the person joined instead of by the employer, or partly by that person and partly by the employer, as the tribunal may consider just and equitable in the circumstances.