102.—(1) An act is not protected if one of the facts relied on for the purpose of establishing liability is that there has been secondary action which is not lawful picketing.
(2) There is secondary action in relation to a trade dispute when, and only when, a person—
(a)induces another to break a contract of employment or interferes or induces another to interfere with its performance, or
(b)threatens that a contract of employment under which he or another is employed will be broken or its performance interfered with, or that he will induce another to break a contract of employment or to interfere with its performance, and the employer under the contract of employment is not the employer party to the dispute.
(3) Lawful picketing means acts done in the course of such attendance as is declared lawful by Article 98 (peaceful picketing)—
(a)by a worker employed (or, in the case of a worker not in employment, last employed) by the employer party to the dispute, or
(b)by a trade union official whose attendance is lawful by virtue of paragraph (1)(b) of that Article.
(4) For the purposes of this Article an employer shall not be treated as party to a dispute between another employer and workers of that employer; and where more than one employer is in dispute with his workers, the dispute between each employer and his workers shall be treated as a separate dispute, In this paragraph “worker” has the same meaning as in Article 127 (meaning of “trade dispute”).
(5) An act in contemplation or furtherance of a trade dispute which is primary action in relation to that dispute may not be relied on as secondary action in relation to another trade dispute. Primary action means such action as is mentioned in sub-paragraph
(a)or (b) of paragraph (2) where the employer under the contract of employment is the employer party to the dispute.
(6) In this article “contract of employment” includes any contract under which one person personally does work or performs services for another, and related expressions shall be construed accordingly.