Introduction
The doctrine of restraint of trade concerns contractual clauses that seek to restrict a person's freedom to exercise their trade, business, or profession. English contract law has long grappled with the tension between two competing public policy objectives: the principle of freedom of contract, which suggests parties should be bound by the terms they agree, and the principle that competition should be encouraged and individuals should be free to earn a livelihood. This has led to a legal position where such clauses are treated with suspicion. The starting point is that any clause in restraint of trade is prima facie void and unenforceable. However, the law has developed to permit such clauses where they can be justified as being reasonable. This essay will critically analyse the development of these legal principles, tracing the evolution from a near-absolute prohibition to the modern test of reasonableness. It will argue that while the modern test provides necessary flexibility, its application, particularly the distinction drawn between employment contracts and the sale of a business, demonstrates a pragmatic but sometimes uncertain judicial balancing act.
From Prohibition to Reasonableness: The Historical Development
The early common law position was one of strict hostility towards any agreement that fettered a person’s liberty to trade. This was evident in Dyer’s Case (1414) YB 2 Hen V, f.5, pl.26, where a dyer had promised not to practice his trade in the same town as the plaintiff for six months. The court reacted angrily, refusing to enforce the bond and allegedly threatening to fine the plaintiff for bringing such a case. This reflected the societal structure of the time, where an individual's trade was often their only means of survival and the public had an interest in ensuring skilled craftsmen were available.
However, as commerce and industry evolved, the courts began to recognise that a blanket prohibition on all restraints was commercially unworkable. A more nuanced approach emerged in the landmark case of Mitchel v Reynolds (1711) 1 P Wms 181. Here, the court distinguished between 'general' restraints, which were unlimited in scope and remained void, and 'partial' restraints, which were limited in time or geographical area. Lord Macclesfield held that a partial restraint could be valid if it was supported by good consideration and was reasonable in the circumstances. This case marked a pivotal shift, introducing the concept of reasonableness as the key criterion for enforceability and laying the groundwork for the modern doctrine.
The definitive modern principles were established by the House of Lords in Nordenfelt v Maxim Nordenfelt Guns and Ammunition Co Ltd [1894] AC 535. Nordenfelt, an armaments inventor, sold his business and agreed not to compete with the buyer anywhere in the world for 25 years. The House of Lords held that the distinction between general and partial restraints was no longer the guiding rule. Instead, the true test was whether the restraint was reasonable. Lord Macnaghten articulated a two-part test: the clause must be reasonable in the interests of the parties and reasonable in the interests of the public. To be reasonable between the parties, the restraint must do no more than afford adequate protection to the party in whose favour it is imposed. In Nordenfelt, the worldwide scope of the restraint was deemed reasonable because the business was international and its customers were governments across the globe. This case cemented reasonableness as the central principle, moving the law away from rigid geographical rules towards a more flexible, fact-based assessment.
The Modern Test: Legitimate Interest and Reasonableness
Following Nordenfelt, for a restraint of trade clause to be enforceable, the covenantee (the party benefiting from the clause) must demonstrate two things. Firstly, that they have a legitimate proprietary interest to protect, and secondly, that the clause is reasonable in scope to protect that interest.
The requirement of a legitimate interest is fundamental. The courts will not enforce a clause that simply seeks to prevent competition per se. In Herbert Morris Ltd v Saxelby [1916] 1 AC 688, Lord Parker stated that an employer is not entitled to protect themselves against competition from a former employee who simply uses the skill and knowledge acquired during their employment. The employer must show an interest in something more concrete, such as trade secrets, confidential information, or customer connections. This ensures that the doctrine is used to protect genuine business assets, not to stifle legitimate competition from former employees or business partners.
Once a legitimate interest is established, the clause must be shown to be reasonable in its scope. This assessment typically involves considering three factors: the geographical area of the restraint, its duration, and the range of activities it seeks to prevent. The clause must be no wider than is necessary to protect the identified interest. For example, in Mason v Provident Clothing & Supply Co Ltd [1913] AC 724, a restraint preventing a canvasser from working in a similar business within 25 miles of London was held to be unreasonable. The employee had only worked in Islington, a small part of that area, so the geographical scope was far wider than necessary to protect the employer’s customer connections in that specific district. Similarly, the duration must be appropriate. While in Fitch v Dewes [1921] 2 AC 158 a lifelong restraint on a solicitor’s managing clerk was upheld due to his intimate knowledge of the firm’s clients, this is exceptional. A shorter period is usually all that is required to allow an employer to shore up their client relationships or for the confidentiality of information to expire.
The Application of the Doctrine in Context
The courts’ application of the reasonableness test is not uniform and varies significantly depending on the context of the agreement. A clear distinction is drawn between clauses in employment contracts and those connected to the sale of a business.
In employment contracts, the courts adopt a stricter approach. This is primarily due to the presumed inequality of bargaining power between the employer and the employee. An employee may feel compelled to accept onerous terms to secure a job, and the law recognises a public interest in allowing individuals to freely use their skills to earn a living. As established in Herbert Morris v Saxelby, the courts are vigilant in ensuring that the employer is protecting a genuine proprietary interest and not merely seeking to prevent the employee from competing.
By contrast, the courts are far more willing to enforce restraints in contracts for the sale of a business. In this context, the parties are typically on a more equal footing in terms of bargaining power. The purchase price of the business will include a sum for 'goodwill', which represents the established reputation and customer base of the business. The purchaser has a clear and legitimate interest in protecting this goodwill from competition by the seller, who is best placed to undermine it. As Lord Macnaghten noted in Nordenfelt, it would be unfair to allow the seller to "derogate from his grant" by setting up a rival business that takes back the very goodwill they have sold. For this reason, wider and longer restraints are more likely to be considered reasonable in business sale agreements.
This contextual approach, while pragmatic, introduces a degree of uncertainty. The reasonableness test is inherently fact-sensitive, meaning that the enforceability of a clause can only be determined with certainty through litigation. This can make it difficult for employers and employees to draft or agree to clauses with confidence, as what is deemed reasonable in one case may not be in another, even with seemingly similar facts. Furthermore, the ability of the courts to sever unreasonable parts of a clause using the 'blue pencil test' (as seen in Attwood v Lamont [1920] 3 KB 571) can sometimes save a poorly drafted clause, but the test is restrictive as the court cannot rewrite the contract, only strike out offending words.
Conclusion
The legal principles governing restraint of trade have undergone a significant evolution from an absolute ban to a flexible, policy-driven test of reasonableness. The modern doctrine, founded on the principles in Nordenfelt, attempts to balance the sanctity of contract against the public interest in competition and individual economic freedom. The core requirements that the covenantee must have a legitimate interest to protect and that the clause must be reasonable in scope provide a structured framework for this balancing act. However, the critical analysis shows that the application of these principles is not always straightforward. The divergent approaches taken in employment contracts and business sales reflect a pragmatic judicial response to different commercial realities and power dynamics. While this contextual flexibility allows the law to adapt to individual circumstances, it comes at the cost of legal certainty. The development of the doctrine thus illustrates a continuous judicial effort to mediate between competing interests, resulting in a body of law that is both commercially necessary and inherently imprecise.
References
Attwood v Lamont [1920] 3 KB 571
Dyer’s Case (1414) YB 2 Hen V, f.5, pl.26
Fitch v Dewes [1921] 2 AC 158
Herbert Morris Ltd v Saxelby [1916] 1 AC 688
Mason v Provident Clothing & Supply Co Ltd [1913] AC 724
Mitchel v Reynolds (1711) 1 P Wms 181
Nordenfelt v Maxim Nordenfelt Guns and Ammunition Co Ltd [1894] AC 535
