## Introduction

In England and Wales, “law” and “equity” describe two strands of the common law tradition. The common law applies rules drawn from statutes and precedent, usually awarding damages for loss. Equity developed to prevent unfair results where strict rules fell short. It focuses on fairness and conscience, offering flexible remedies such as specific performance, injunctions, rescission, rectification, constructive trusts, and accounts of profits.

Historically, the common law and the Court of Chancery operated separately. The Judicature Acts 1873–1875 brought their administration into a single court system. Modern courts apply both sets of principles. Where the two conflict, equity prevails. Because many equitable remedies are discretionary, the claimant’s conduct matters: clean hands and prompt action count; delay (laches) and unfair behaviour can bar relief.

This guide explains the key differences, the main remedies and maxims, leading cases, and how to apply the principles in everyday legal problems.

## What You’ll Learn

- How common law and equity developed and why both still matter
- The difference between legal rights and equitable rights
- When damages are “adequate” and when equitable remedies are likely
- Key equitable maxims (clean hands, laches, volunteers, equity follows the law)
- Priority rules affecting equitable interests and third parties
- Landmark cases, including Earl of Oxford’s Case, Walsh v Lonsdale, High Trees, American Cyanamid, and Argyll Stores
- Practical steps for choosing and framing remedies in contracts, tort, property, and trusts

## Core Concepts

### What the Common Law Provides

- Rules and remedies drawn from statutes and precedent, applied consistently across cases.
- Primary remedy: damages to compensate for loss (expectation loss in contract; compensatory damages in tort).
- Suits are generally about rights enforceable against the world (in rem) or against individuals (in personam), but with standardised outcomes.
- Courts are slow to make orders that require continuous supervision or involve personal services.

Key points:

- Damages aim to put the claimant in the position they would have been in had the duty not been breached.
- Specific performance and injunctions are not common law remedies.

### What Equity Adds

- Equity acts to prevent unfair results where damages are not enough.
- Equitable remedies are discretionary; the court may refuse them if it would be unfair to grant them.
- Equity looks closely at conduct. Clean hands and prompt action are important; delay may defeat the claim (laches).
- Equity typically acts in personam: orders bind the defendant personally, backed by contempt sanctions.

Common equitable rights and doctrines:

- Beneficial interests under a trust
- Equity of redemption in mortgages
- Proprietary estoppel and promissory estoppel
- Equitable mortgages and charges
- Constructive and resulting trusts

Maxim to remember:

- Equity follows the law: equity respects legal rights and rules unless fairness requires a different outcome.

### Legal vs Equitable Remedies

When damages are likely:

- Standard commercial breaches where a sum of money can fairly compensate the claimant.
- Losses can be measured and the subject matter is not unique.

When equitable relief is considered:

- Specific performance: typically for unique goods (antique, art) or land. Not granted where it would require constant supervision or for personal services.
- Injunctions: to prevent threatened or ongoing wrongful acts. Interim injunctions follow the American Cyanamid test (serious question to try, adequacy of damages, balance of convenience, and overall justice). An undertaking in damages is usually required.
- Rescission: sets aside a contract for misrepresentation, undue influence, or certain mistakes, subject to bars such as affirmation or impossibility of restoration.
- Rectification: corrects a written instrument that fails to reflect a prior common intention.
- Account of profits: strips wrongful gains (e.g., breach of confidence, certain IP contexts).
- Constructive trust: imposes a trust to address wrongful enrichment or to recognise shared ownership where fairness requires it.

### Equitable Maxims and Defences

- He who seeks equity must do equity: the claimant may need to meet conditions (e.g., pay what is owed) to obtain relief.
- He who comes to equity must come with clean hands: misconduct connected to the claim may bar relief.
- Delay defeats equity (laches): unreasonable delay that prejudices the defendant can stop a claim.
- Equity will not assist a volunteer: those who have not given value are usually not protected against third parties.
- Equity regards as done that which ought to be done: particularly relevant to contracts for the sale of land and equitable interests arising from enforceable agreements.
- Equity looks to the intent rather than the form: substance matters more than technicalities.

These are guides, not rigid rules. The court weighs them against the facts and the justice of the case.

### Priorities and Third Parties

- Equitable rights can bind third parties except a bona fide purchaser for value of a legal estate without notice (often called “equity’s darling”).
- Notice can be actual, constructive, or imputed. A purchaser who should have discovered the equitable interest may be fixed with constructive notice.
- Registration regimes (e.g., Land Registration Act 2002) affect priority in land, but equitable concepts still matter: consider occupation, restrictions, and the state of the register.

### Administrative Merger: What It Means Today

- Since the Judicature Acts 1873–1875, all divisions of the High Court may apply both common law and equitable principles.
- The Chancery Division still hears many equity-heavy matters (trusts, mortgages, company law), but any court can grant equitable relief where appropriate.
- Where there is a conflict, equity prevails. The labels “legal” and “equitable” continue to matter for remedies, priorities, and defences.

## Key Examples or Case Studies

### The Earl of Oxford’s Case (1615)

- Context: Conflict between a common law judgment and a contrary equitable position.
- Key point: When law and equity conflict, equity prevails.
- Application: Modern courts may refuse to enforce strict legal rights where doing so would be unfair, opting for an equitable solution.

### Walsh v Lonsdale (1882) 21 Ch D 9

- Context: Agreement to grant a lease was specifically enforceable though not perfected at law.
- Key point: Equity regards as done that which ought to be done. An enforceable contract can create an equitable lease.
- Application: In property and commercial deals, an enforceable agreement may give rise to equitable rights even before formalities are completed.

### Central London Property Trust Ltd v High Trees House Ltd [1947] KB 130

- Context: Landlord agreed to reduce rent during wartime; sought full rent for that period later.
- Key point: Promissory estoppel can prevent a party from insisting on strict legal rights where the other party relied on a promise.
- Application: Use estoppel to resist claims inconsistent with earlier assurances, subject to fairness and the limits of the doctrine.

### American Cyanamid Co v Ethicon Ltd [1975] AC 396

- Context: Interim injunction for alleged patent infringement.
- Key point: Interim injunction test: serious question to try; damages adequacy; balance of convenience; overall justice. Undertakings in damages are standard.
- Application: When urgent relief is needed, prepare evidence on why damages won’t be enough and how the balance favours an injunction.

### Co‑operative Insurance Society Ltd v Argyll Stores (Holdings) Ltd [1998] AC 1

- Context: Tenant of a shopping centre covenant to keep a supermarket open.
- Key point: Specific performance refused for obligations requiring constant supervision and ongoing business operations.
- Application: Seek damages or a negative injunction instead of forcing ongoing performance of complex obligations.

## Practical Applications

- Start with the remedy: Ask whether damages are adequate. If not, consider specific performance, injunction, or restitutionary remedies.
- Check conduct: Prepare for clean hands and laches questions. Gather evidence explaining any delay and demonstrating fair behaviour.
- Plead in the alternative: Claim damages and, where appropriate, equitable relief. Be clear on what order you want and why it is fair.
- Evidence for interim relief: Address American Cyanamid factors, provide an undertaking in damages, and show practical workability of the order.
- Watch for bars to rescission and rectification: Affirmation, third‑party rights, impossibility of restoring parties to their pre‑contract position, or lack of a prior common intention can all block relief.
- Property and trusts: Identify legal title and any equitable interests. Consider whether a purchaser is with or without notice and whether registration affects priority.
- Volunteers: If a claimant gave no value, expect difficulties enforcing equitable rights against third parties.
- Drafting and transactions: Use clear terms, complete formalities promptly, and record intentions. This reduces arguments about rectification and constructive trusts.
- Settlement: Many equitable disputes are fact‑sensitive. Evaluate early settlement where outcomes carry uncertainty due to discretion.

## Summary Checklist

- Can money fix the problem? If not, consider equitable remedies.
- Has the claimant delayed or acted unfairly? Expect laches or clean hands issues.
- Is the order workable? Courts avoid orders needing constant supervision.
- For interim injunctions, cover all American Cyanamid factors and give an undertaking.
- In property matters, check for equitable interests, notice, and registration.
- Use estoppel carefully; it typically suspends rights and depends on fairness.
- Where law and equity clash, equity prevails—subject to the rights of good‑faith purchasers.
- Always plead in the alternative and back up discretionary relief with practical detail.

## Quick Reference

| Concept                               | Authority                         | Key takeaway                                                   |
| ------------------------------------- | --------------------------------- | -------------------------------------------------------------- |
| Equity prevails in a conflict         | Earl of Oxford’s Case (1615)      | Courts prefer equitable outcomes over strict legal rights      |
| Interim injunction test               | American Cyanamid [1975] AC 396   | Serious question, damages adequacy, balance, overall justice   |
| Specific performance limits           | Argyll Stores [1998] AC 1         | No orders for continuous supervision or running a business     |
| Equitable lease from enforceable deal | Walsh v Lonsdale (1882) 21 Ch D 9 | Equity treats the agreement as if granted                      |
| Promissory estoppel                   | High Trees [1947] KB 130          | Parties may be stopped from going back on relied‑upon promises |
| Administrative merger of courts       | Judicature Acts 1873–1875         | One court system applies both law and equity                   |


Law and Equity: Principles, Remedies, and Modern Relevance