Fiduciary Duty in UK Law

A fiduciary is someone who has undertaken to act for or on behalf of another in a particular matter in circumstances which give rise to a relationship of trust and confidence. A fiduciary must act in good faith; he must not make a profit out of his trust; he must not place himself in a position where his duty and his interest may conflict; he may not act for his own benefit or the benefit of a third person without the informed consent of his principal.

A fiduciary who acts for two principals with potentially conflicting interests without the informed consent of both is in breach of the obligation of undivided loyalty; he puts himself in a position where his duty to one principal may conflict with his duty to the other: see Clark Boyce v Mouat [1994] 1 AC 428 and the cases there cited. This is sometimes described as "the double employment rule". Breach of the rule automatically constitutes a breach of fiduciary duty.

Even if a fiduciary is properly acting for two principals with potentially conflicting interests he must act in good faith in the interests of each and must not act with the intention of furthering the interests of one principal to the prejudice of those of the other: see Finn (op.cit.) He must not allow the performance of his obligations to one principal to be influenced by his relationship with the other. He must serve each as faithfully and loyally as if he were his only principal.

The rule of equity which insists on those who by use of a fiduciary position make a profit, being liable to account for that profit, in no way depends on fraud, or absence of bona fides; or upon such questions or considerations as whether the profit would or should otherwise have gone to the Plaintiff, or whether the profiteer was under a duty to obtain the source of the profit for the Plaintiff, or whether he took a risk, or acted as he did for the benefit of the Plaintiff, or whether the Plaintiff has in fact been damaged or benefited by his action.

Furthermore, if in a sphere in which a person is so placed that others could reasonably rely upon his judgment or his skill or upon his ability to make careful inquiry, a person takes it upon himself to give information or advice to, or allows his information or advice to be passed on to, another person who, as he knows or should know, will place reliance upon it, then a duty of care will arise.

If it is voidable, then it may be capable of being set aside at the suit of a beneficiary, but this would be subject to equitable defences and to the court's discretion. The trustees' duty to take relevant matters into account is a fiduciary duty, so an act done as a result of a breach of that duty is voidable. Fiscal considerations will often be among the relevant matters which ought to be taken into account.

The relevant rule, which Lord Cranworth LC in Aberdeen Railway Co v. Blaikie described as being "of universal application", and which Lord Herschell in Bray v. Ford [1896] AC 44 at 51, described as "inflexible", is that (to use Lord Cranworth's formulation) no fiduciary "shall be allowed to enter into engagements in which he has, or can have, a personal interest conflicting, or which may possibly conflict, with the interests of those whom he is bound to protect".