您好，retraint of trade clause 本身是不合法的，除非雇主可以证明这类型的限制的合理性。
法庭对如何是合理有以下看法：
In considering whether the restraint was reasonable in all the circumstances the Court has regard to the history of the employment, the nature of the employer's interest to be protected, the likely effect on the former employee taking up a position with a copetitor of the empployer, the likely effect on the employee of the covenant being enfored, and any relevant considerations of public interest that suggest themselves.