A supplier’s lien is a right for a supplier of goods or services to retain possession of a customer’s property until payment of sums due. In practice, it operates as a form of security: the supplier is not obliged to release the goods (or documents relating to them) until outstanding invoices are settled.In England and Wales, Northern Ireland and Ireland, a supplier’s lien usually arises either under an express contractual clause (often drafted as a “particular” or “general” lien) or under common law principles of particular lien, where the supplier has improved or worked on goods. In Scotland, similar rights exist under possessory lien and retention, generally requiring continuous lawful possession.A supplier’s lien is a possessory remedy only: it does not normally confer a power of sale, which must be expressly agreed or arise under specific statutory regimes. Loss of possession typically extinguishes the lien.The term is descriptive rather than a single codified concept, and its scope and enforceability depend on the underlying contract, applicable common law or case law, and any relevant statutory provisions on sale of goods, insolvency, or security rights in the particular UK or Irish jurisdiction.

In legal practice, a change of circumstances is a supervening event that materially alters the facts on which a right, obligation, order or valuation was based.It is a descriptive expression, not a defined term. In contract law across the UK and Ireland, such changes may engage a force majeure clause or, exceptionally, the doctrine of frustration (where performance becomes impossible or radically different).In family law, parties commonly invoke a material change of circumstances to seek variation, suspension or discharge of periodical payments (spousal maintenance) and child maintenance/support, or to vary child arrangements/contact orders. Variation is governed by statute and case law: for example the Matrimonial Causes Act 1973, the Child Support Act 1991 (Great Britain) and the Child Support (Northern Ireland) Order 1991, and in Ireland the Family Law (Maintenance of Spouses and Children) Act 1976 and Family Law (Divorce) Act 1996. Decision‑makers assess materiality, durability and fairness; a child’s welfare is paramount.In rating/valuation, a material change of circumstances (MCC) can justify altering a non‑domestic rating list on appeal, typically for physical changes to the hereditament or its locality, under the Local Government Finance Act 1988, with analogous regimes in Scotland, Northern Ireland and Ireland.

An operative fact is a fact or event that has direct legal effect in itself, giving rise to, altering or extinguishing legal rights or obligations, rather than merely providing evidence of them. In practice, it is a fact that the law treats as constitutive of a legal relationship or consequence, for example: making a contractual offer and acceptance, serving a statutory notice, publishing an allegedly defamatory statement, or committing a tortious or criminal act.The expression “operative fact” is largely descriptive and doctrinal rather than a defined statutory term in the UK or Ireland. It is used in litigation, legal drafting and legal analysis to distinguish between: (i) facts that create or change legal rights (operative facts) and (ii) evidential facts used to prove those operative facts.Identifying operative facts is central to pleading a cause of action, framing issues for trial, advising on limitation, and assessing remedies. Usage is broadly consistent across England and Wales, Scotland, Northern Ireland and Ireland, including in contract law, tort/delict, property law and public law, although particular operative facts will depend on the substantive legal rules of each jurisdiction.

Permissive waste describes loss or deterioration of land or buildings caused by a tenant’s failure to take reasonable care, rather than by positive damaging acts. It typically arises where a leaseholder, life tenant or other occupier does not carry out basic maintenance, allows disrepair to develop, or fails to comply with obligations to keep premises in repair, leading to a reduction in the value of the landlord’s or reversioner’s interest.In England and Wales and Northern Ireland, permissive waste is rooted in common law and equity, mainly developed through case law rather than detailed statutory definition, and can be actionable as a breach of covenant to repair or as a claim in waste. It is relevant in leasehold, trust, life interest, and mortgage contexts.In Ireland, the concept is similarly recognised at common law, again primarily in the context of landlord and tenant and life interests.In Scotland, “waste” language is less common, but a broadly equivalent idea appears in obligations on tenants and liferenters to avoid allowing heritable property to fall into dilapidation through neglect, enforceable under contract and property law principles.

Express notice describes a situation where a person is told, clearly and directly, about a legal right, claim, fact or restriction, so they have actual knowledge of it. It contrasts with constructive or imputed notice, where knowledge is attributed by law. Express notice commonly takes the form of a written notice under a contract, an email or letter identifying the relevant right, or wording apparent on the face of a document received.The term is descriptive and used across contexts. In unregistered land and equity, express notice prevents a purchaser claiming to be a bona fide purchaser without notice. In registered land (England and Wales/Northern Ireland), priority is governed mainly by registration rules (e.g. Land Registration Act 2002), but express notice may still be relevant to equitable claims and estoppel.Assignments frequently require express written notice to the debtor to be effective at law or to secure priority (e.g. section 136 Law of Property Act 1925 in England and Wales; equivalent statutory rules in Northern Ireland and Ireland). In Scotland, intimation to the debtor (now alternatively registration under the Moveable Transactions (Scotland) Act 2023) serves a similar function.Contract schemes often require express notice to trigger termination, warranty claims or time bars; strict compliance with form, content, service and timing requirements is essential. Usage is broadly consistent across the UK and Ireland.

A joint defendant is a person or entity sued together with one or more others in the same legal proceedings, usually because they are alleged to be jointly or jointly and severally liable for the same wrong or obligation. The term is descriptive rather than formally defined in legislation, but is widely used in civil and criminal practice across England and Wales, Scotland, Northern Ireland and Ireland with broadly consistent meaning.In civil litigation, joint defendants commonly arise in claims for breach of contract, professional negligence, personal injury, construction disputes and contribution or indemnity claims, where responsibility or causation is contested between multiple parties. The status of joint defendant affects issues such as case management, disclosure, apportionment of liability, contribution between wrongdoers, costs orders and enforcement of judgments.In criminal proceedings, joint defendants (or “co‑accused” in Scottish practice) are individuals charged on the same indictment or complaint, often where joint enterprise, common purpose or conspiracy is alleged. Their joinder has procedural implications for admissibility of evidence, severance applications and directions to the jury.Rules on adding, removing or substituting joint defendants are governed by court rules (for example, CPR, RSC, Rules of the Court of Session) and relevant case law in each jurisdiction.

A self-employed person is an individual who works for themselves, usually carrying on a business, trade or profession on their own account, and does not work under a contract of employment. In legal practice, the concept is central to employment status disputes, tax treatment, social security, vicarious liability and pensions.Across England & Wales, Scotland and Northern Ireland, “self-employed” is a descriptive term rather than a single statutory status, but it is reflected in legislation and case law, including employment rights and income tax provisions. The courts focus on factors such as control, mutuality of obligation, the right of substitution, financial risk, provision of equipment, opportunity for profit, and how the parties have labelled the relationship.In Ireland, the concept is similarly developed through tax and employment legislation and case law, using comparable multi-factor tests to distinguish employees from self‑employed contractors.Self-employed status generally excludes the individual from core employee and “worker” protections, such as unfair dismissal and most statutory leave, but may allow greater autonomy and tax deductibility of business expenses. Classification errors can give rise to liabilities for PAYE/PRSI, National Insurance contributions, holiday pay, and regulatory non-compliance.

Small claims court refers, in practical terms, to the forum or procedural track for resolving low‑value civil disputes using simplified, largely informal procedures and limited costs risk. It is a descriptive expression rather than a formal, consistently defined statutory term across the UK and Ireland.In England and Wales, it usually means the small claims track in the County Court (Civil Procedure Rules Part 27), commonly used for consumer disputes, unpaid invoices, minor contract and tort claims. In Scotland, it broadly corresponds to the simple procedure in the sheriff court (covering most lower‑value civil claims), and historically to the “small claims” procedure it replaced. In Northern Ireland, it usually denotes the small claims procedure in the county court, governed by specific rules and value limits. In Ireland, it refers to the Small Claims Procedure in the District Court, primarily for consumer and certain business claims, under District Court Rules.Key features across jurisdictions include restricted legal costs recovery, judge‑led hearings, encouragement of self‑representation, prescribed monetary limits, and streamlined forms and evidential rules, making it a central mechanism for proportionate dispute resolution.

Emotional distress describes psychological suffering (anxiety, humiliation, anguish or upset) claimed as harm or as a head of damages. It is not a defined legal term; courts in England & Wales, Scotland, Northern Ireland and Ireland commonly refer to psychiatric injury, nervous shock, distress or injury to feelings.In negligence, compensation usually requires a recognised psychiatric illness; mere distress, grief or worry is insufficient. Control tests apply (primary/secondary victim rules in England & Wales and Northern Ireland; analogous tests in Scotland; in Ireland, the Kelly v Hennessey criteria).Distress without clinical illness can be recoverable where specific regimes allow it, including:- Harassment (Protection from Harassment Act 1997 in England & Wales and Scotland; Protection from Harassment (Northern Ireland) Order 1997);- Data protection (UK GDPR/Data Protection Act 2018; EU GDPR in Ireland) for non-material damage;- Discrimination and whistleblowing detriment (Equality Act 2010 and NI/Irish equivalents) via injury to feelings;- Defamation/misuse of private information; and- Contract where the object is pleasure or peace of mind.Practically, plead the correct head of loss and evidence: medical diagnosis for psychiatric injury; factual impact for injury to feelings. Usage is broadly consistent across the jurisdictions, subject to the noted tests.

A right of entry is the legal entitlement to go onto another’s land or into premises without committing trespass, arising from contract (especially leases), property rights, or statute. The term is descriptive and used across contexts; particular powers are defined and limited by specific legislation and case law.In leases, a landlord’s right of entry to inspect, repair or comply with obligations is usually an express covenant, exercisable for stated purposes, on reasonable notice and at reasonable times; it does not permit harassment or use beyond its purpose, and refusal typically requires a court order or injunction rather than self-help.A distinct concept is the right of re-entry on breach (forfeiture/termination). In England & Wales (and broadly in Northern Ireland) this generally requires prior statutory notice (e.g. section 146 Law of Property Act 1925), and “peaceable re-entry” is restricted, particularly for dwellings. In Scotland, the equivalent remedy is irritancy, governed by common law and statute, with notice requirements. In Ireland, forfeiture/termination proceeds by court order under landlord and tenant legislation.Statutory rights of entry (e.g. for regulators, police, planning/building control, utilities) and easements/servitudes or wayleaves permit access for defined purposes, often with notice, warrant and compensation safeguards.

Will substitutes are arrangements that pass property on death outside the terms of a will and outside the formal requirements for making a will. The expression is descriptive rather than a defined statutory term in the UK or Ireland, but is widely used in private client practice and academic commentary.Typical will substitutes include nominations (for example, in pension schemes or certain credit union accounts), joint tenancies/right of survivorship, life assurance written in trust, payable‑on‑death clauses in some investment products, and lifetime trusts where the settlor retains benefits until death. These mechanisms take effect by survivorship, contract or trust law rather than succession law, and generally do not form part of the deceased’s probate estate (or, in Scotland, estate for confirmation), though they may still be relevant for inheritance tax or legal rights/forced heirship claims.Usage is broadly consistent across England & Wales, Scotland, Northern Ireland and Ireland, but practitioners must consider jurisdiction‑specific rules on matrimonial property, clawback, legal rights in Scotland and section 117 Succession Act 1965 in Ireland, as well as financial provision on divorce or death. Will substitutes are central to estate planning, probate risk management and contentious succession work.

An inventor is the natural person who has made the original inventive contribution embodied in an invention, typically reflected in a patent application or granted patent. In UK law (England & Wales, Scotland and Northern Ireland), the concept is principally defined in the Patents Act 1977, which treats the inventor as the “actual deviser” of the invention. Irish law adopts a broadly similar approach under the Patents Act 1992, focussing on the person who created the invention.In all these jurisdictions, only individuals (not companies) can be inventors, although employers and others may acquire ownership (patent entitlement) by statute, contract or assignment. Joint inventors arise where more than one person contributes materially to the inventive concept.Correct identification and naming of the inventor in patent applications is legally and commercially significant, affecting entitlement disputes, employee compensation claims, validity challenges and enforceability of patent rights. Misidentification can lead to rectification proceedings or, in some circumstances, revocation.Across the UK and Ireland, the term “inventor” is used consistently in patent law, patent litigation, technology transfer, R&D agreements and employee invention policies, and is central when advising on ownership, exploitation and infringement of patent-protected technology.