What is the legal test for a servant who procures a man to commit a breach of contract with a third party?

In answering this question, I think the starting point is the decision of McCardie J. in Said v. Butt, [1920] 3 K.B. 497. At pp. 505-506, he deals with the situation where a person knowingly procures a man to commit a breach of his contract with another and says: If he is in the position of a stranger, he will be prima facie liable, even though he may act honestly, or without malice, or in the best interests of himself … But the servant who causes a breach of his master’s contract with a third person seems to stand in a wholly different position. He is not a stranger. He is the alter ego of his master. His acts are in law the acts of his employer. In such a case it is the master himself, by his agent, breaking the contract he has made … and at p. 506: I hold that if a servant acting bona fide within the scope of his authority procures or causes the breach of a contract between his employer and a third person, he does not thereby become liable to an action of tort at the suit of the person whose contract has thereby been broken. I abstain from expressing any opinion as to the law which may apply if a servant, acting as an entire stranger, or wholly outside the range of his powers, procures his master to wrongfully break a contract with a third person.