18. Immunity from civil suit in certain cases

(1) No suit or other legal proceeding shall be maintainable in any civil court against any registered trade union or any 8[office-bearer] or member thereof in respect of any act done in contemplation or furtherance of a trade dispute to which a member of the trade union is a party on the ground only that such act induces some other person to break a contract of employment, or that it is in interference with the trade, business or employment of some other person or with the right of some other person to dispose of his capital or of his labor as he wills.

(2) A registered trade union shall not be liable in any suit or other legal proceeding in any civil court in respect of any tortious act done in contemplation or furtherance of a trade dispute by an agent of the trade union if it is proved that such person acted without the knowledge of, or contrary to express instructions given by, the executive of the trade union.