As well as showing that the defendant intended the unlawful act, it has to be shown that his intervention had some causal effect. It has to be shown that the wrongful act would or might not have occurred but for the defendant's intervention. It has to be shown that the defendant induced the third party to break his contract or do some other wrongful act. It does not matter what his intervention is called. It may be called information, advice or warning, inducement, persuasion or procurement,