A trustee de son tort is a person who may be regarded as owing fiduciary duties by a course of conduct that amounts to a wrong, or a tort. Accordingly, a trustee de son tort is not a person who is formally appointed as a trustee, but one who assumes such a role, and then cannot be heard to argue that he did not owe fiduciary duties.
The courts may hold a person a constructive trustee instead of prosecuting and, thereby, impose the liabilities of an actual trustee in accounting for his or her acts.
Lewin on Trustssays at 42-74:
If a person by mistake or otherwise assumes the character of trustee when it does not really belong to him, he becomes a trustee de son tort and he may be called to account by the beneficiaries for the money he has received under the colour of the trust. A trustee de son tort closely resembles an express trustee. The principle is that a person who assumes an office ought not to be in a better position than if he were what he pretends; he is accountable as if he had the authority which he has assumed. While it is essential, if a person is to become a trustee de son tort, that he consciously takes the office of trustee, it does not matter whether he knows all the trusts or the extent of his powers.
Thomas and Hudson's The Law on Trustssays at para 30.03:
... trustees de son tort are not expressly declared by the settlor to be trustees but rather are deemed to be constructive trustees by operation of law, due to their meddling with trust affairs, they are therefore constructive trustees.
A "trustee de son tort" is to be contrasted with a delegate who is appointed by a trustee to undertake certain functions: such a person derives his authority from the trustee and is entitled to act in accordance with the delegated authority without himself becoming a trustee. A delegate, in such circumstance, has done no "wrong" and is not intermeddling in the trust and so does not become a “trustee de son tort”.
The court also considered the concept of a trustee de son tort and whether an agent, appointed by a duly constituted trustee, could itself be a trustee de son tort in circumstances where the agent's actions caused loss to the trust fund.
It was argued that it was commonplace in the trust industry for the administration of a trust to be carried out largely by another company (other than the trustee) within the same group of companies as the corporate trustee. It would cause considerable surprise in the industry if such a company was to find itself designated a trustee de son tort. Because it was common practice it was important that an authoritative decision be given as to whether such an administrative company should be treated as a trustee de son tort.
A trust is a legal relationship in which the legal title to property is entrusted to a person or legal entity with a fiduciary duty to hold and use it for another's benefit. In the Anglo-American common law, the party who entrusts the property is known as the "settlor", the party to whom the property is entrusted is known as the "trustee", the party for whose benefit the property is entrusted is known as the "beneficiary", and the entrusted property itself is known as the "corpus" or "trust property".
Trustee is a legal term which, in its broadest sense, is a synonym for anyone in a position of trust and so can refer to any person who holds property, authority, or a position of trust or responsibility to transfer the title of ownership to the person named as the new owner, in a trust instrument, called a beneficiary. A trustee can also refer to a person who is allowed to do certain tasks but not able to gain income, although that is untrue. Although in the strictest sense of the term a trustee is the holder of property on behalf of a beneficiary, the more expansive sense encompasses persons who serve, for example, on the board of trustees of an institution that operates for a charity, for the benefit of the general public, or a person in the local government.
A fiduciary is a person who holds a legal or ethical relationship of trust with one or more other parties. Typically, a fiduciary prudently takes care of money or other assets for another person. One party, for example, a corporate trust company or the trust department of a bank, acts in a fiduciary capacity to another party, who, for example, has entrusted funds to the fiduciary for safekeeping or investment. Likewise, financial advisers, financial planners, and asset managers, including managers of pension plans, endowments, and other tax-exempt assets, are considered fiduciaries under applicable statutes and laws. In a fiduciary relationship, one person, in a position of vulnerability, justifiably vests confidence, good faith, reliance, and trust in another whose aid, advice, or protection is sought in some matter. In such a relation good conscience requires the fiduciary to act at all times for the sole benefit and interest of the one who trusts.
A fiduciary is someone who has undertaken to act for and on behalf of another in a particular matter in circumstances which give rise to a relationship of trust and confidence.
A constructive trust is an equitable remedy imposed by a court to benefit a party that has been wrongfully deprived of its rights due to either a person obtaining or holding a legal property right which they should not possess due to unjust enrichment or interference, or due to a breach of fiduciary duty, which is intercausative with unjust enrichment and/or property interference. It is a type of implied trust.
In commercial law, a principal is a person, legal or natural, who authorizes an agent to act to create one or more legal relationships with a third party. This branch of law is called agency and relies on the common law proposition qui facit per alium, facit per se.
English trust law concerns the creation and protection of asset funds, which are usually held by one party for another's benefit. Trusts were a creation of the English law of property and obligations, but also share a history with countries across the Commonwealth and the United States. Trusts developed when claimants in property disputes were dissatisfied with the common law courts and petitioned the King for a just and equitable result. On the King's behalf, the Lord Chancellor developed a parallel justice system in the Court of Chancery, commonly referred as equity. Historically, trusts were mostly used where people left money in a will, created family settlements, created charities, or some types of business venture. After the Judicature Act 1873, England's courts of equity and common law were merged, and equitable principles took precedence. Today, trusts play an important role in financial investments, especially in unit trusts and pension trusts, where trustees and fund managers usually invest assets for people who wish to save for retirement. Although people are generally free to write trusts in any way they like, an increasing number of statutes are designed to protect beneficiaries, or regulate the trust relationship, including the Trustee Act 1925, Trustee Investments Act 1961, Recognition of Trusts Act 1987, Financial Services and Markets Act 2000, Trustee Act 2000, Pensions Act 1995, Pensions Act 2004 and the Charities Act 2011.
Keech v Sandford EWHC J76 is a foundational case, deriving from English trusts law, on the fiduciary duty of loyalty. It concerns the law of trusts and has affected much of the thinking on directors' duties in company law. It holds that a trustee owes a strict duty of loyalty so that there can never be a possibility of any conflict of interest.
Candler v Crane, Christmas & Co  2 KB 164 is an English tort law case on negligent misstatement.
Dishonest assistance, or knowing assistance, is a type of third party liability under English trust law. It is usually seen as one of two liabilities established in Barnes v Addy, the other one being knowing receipt. To be liable for dishonest assistance, there must be a breach of trust or fiduciary duty by someone other than the defendant, the defendant must have helped that person in the breach, and the defendant must have a dishonest state of mind. The liability itself is well established, but the mental element of dishonesty is subject to considerable controversy which sprang from the House of Lords case Twinsectra Ltd v Yardley.
In English law, secret trusts are a class of trust defined as an arrangement between a testator and a trustee, made to come into force after death, that aims to benefit a person without having been written in a formal will. The property is given to the trustee in the will, and he would then be expected to pass it on to the real beneficiary. For these to be valid, the person seeking to enforce the trust must prove that the testator intended to form a trust, that this intention was communicated to the trustee, and that the trustee accepted his office. There are two types of secret trust — fully secret and half-secret. A fully secret trust is one with no mention in the will whatsoever. In the case of a half-secret trust, the face of the will names the trustee as trustee, but does not give the trust's terms, including the beneficiary. The most important difference lies in communication of the trust: the terms of a half-secret trust must be communicated to the trustee before the execution of the will, whereas in the case of a fully secret trust the terms may be communicated after the execution of the will, as long as this is before the testator's death.
Resulting trusts in English law are trusts created where property is not properly disposed of. It comes from the Latin resultare, meaning to spring back, and was defined by Megarry VC as "essentially a property concept; any property that a man does not effectually dispose of remains his own". These trusts come in two forms: automatic resulting trusts, and presumed resulting trusts. Automatic resulting trusts arise from a "gap" in the equitable title of property. The equitable maxim "equity abhors a vacuum" is followed: it is against principle for a piece of property to have no owner. As such, the courts assign the property to somebody in a resulting trust to avoid this becoming an issue. They occur in one of four situations: where there is no declaration of trust, where an express trust fails, where there is surplus property, or upon the dissolution of an unincorporated association. Rules differ depending on the situation and the type of original trust under dispute; failed charitable trusts, for example, have the property reapplied in a different way from other forms of trust.
Constructive trusts in English law are a form of trust created by the English law courts primarily where the defendant has dealt with property in an "unconscionable manner"—but also in other circumstances. The property is held in "constructive trust" for the harmed party, obliging the defendant to look after it. The main factors that lead to a constructive trust are unconscionable dealings with property, profits from unlawful acts, and unauthorised profits by a fiduciary. Where the owner of a property deals with it in a way that denies or impedes the rights of some other person over that property, the courts may order that owner to hold it in constructive trust. Where someone profits from unlawful acts, such as murder, fraud, or bribery, these profits may also be held in constructive trust. The most common of these is bribery, which requires that the person be in a fiduciary office. Certain offices, such as those of trustee and company director, are always fiduciary offices. Courts may recognise others where the circumstances demand it. Where someone in a fiduciary office makes profits from their duties without the authorisation of that office's beneficiaries, a constructive trust may be imposed on those profits; there is a defence where the beneficiaries have authorised such profits. The justification here is that a person in such an office must avoid conflicts of interest, and be held to account should he fail to do so.
Tracing in English law is a procedure to identify property that has been taken from the claimant involuntarily. It is not in itself a way to recover the property, but rather to identify it so that the courts can decide what remedy to apply. The procedure is used in several situations, broadly demarcated by whether the property has been transferred because of theft, breach of trust, or mistake.
Trustor AB v Smallbone  EWHC 703 (Ch) is a UK company law case concerning piercing the corporate veil.
The Attorney General for Hong Kong v Reid (UKPC) UKPC 2 UKPC 1993_36 was a New Zealand-originated trust law case heard and decided by the Judicial Committee of the Privy Council, where it was held that bribe money accepted by a person in a position of trust, can be traced into any property bought and is held on constructive trust for the beneficiary.
Westdeutsche Landesbank Girozentrale v Islington LBC UKHL 12 is a leading English trusts law case concerning the circumstances under which a resulting trust arises. It held that such a trust must be intended, or must be able to be presumed to have been intended. In the view of the majority of the House of Lords, presumed intention to reflect what is conscionable underlies all resulting and constructive trusts.
Oldham v Kyrris EWCA Civ 1506 is a UK insolvency law case concerning the administration procedure when a company is unable to repay its debts.
Sinclair Investments (UK) Ltd v Versailles Trade Finance Ltd EWCA Civ 347 is an English trusts law case, concerning constructive trusts. Sinclair was partially overruled in July 2014 by the UK Supreme Court in FHR European Ventures LLP v Cedar Capital Partners LLC.
Re Hallett’s Estate (1880) 13 Ch D 696 is an English trusts law case, concerning asset tracing.
FHR European Ventures LLP v Cedar Capital Partners LLC UKSC 45 is a landmark decision of the United Kingdom Supreme Court which holds that a bribe or secret commission accepted by an agent is held on trust for his principal. In so ruling, the Court partially overruled Sinclair Investments (UK) Ltd v Versailles Trade Finance Ltd in favour of The Attorney General for Hong Kong v Reid (UKPC), a ruling from the Judicial Committee of the Privy Council on appeal from New Zealand.