A departing employee joining a competitor can create an immediate commercial risk, particularly where they know your clients, pricing, business plans or key personnel. Understanding how to enforce restrictive covenants quickly and lawfully can protect those interests, but an employer cannot simply rely on a clause because it appears in a contract. The restriction must be carefully assessed before action is taken.
Start with the covenant and the risk
Restrictive covenants are contractual terms intended to limit what an employee can do after their employment ends. They are commonly included in contracts for senior employees, sales staff, professionals and employees with access to sensitive information or influential client relationships.
The most common provisions prevent a former employee from soliciting or dealing with clients, poaching colleagues, working for a competing business, or using confidential information. A non-compete clause is usually the most difficult to enforce because it directly restricts someone’s ability to work.
The starting point is not whether the employee has left on difficult terms. It is whether there is a genuine and identifiable threat to a legitimate business interest. For example, a former account director approaching clients they managed shortly before leaving may present a stronger case than an employee simply taking a role in the same broad sector.
When are restrictive covenants enforceable?
Under English law, restrictive covenants are generally void as restraints of trade unless an employer can show that the restriction protects a legitimate business interest and goes no further than reasonably necessary to do so.
Legitimate interests may include confidential information, customer connections, supplier relationships and the stability of the workforce. Preventing ordinary competition, or trying to keep an employee out of the market because their departure is unwelcome, is not enough.
Reasonableness depends on the wording of the clause and the employee’s role at the time the contract was agreed. The court will consider matters such as the length of the restriction, its geographical reach, the clients or employees covered, the nature of the employee’s access to information, and whether a less restrictive clause would have protected the business.
A six-month non-solicitation restriction limited to clients with whom a senior salesperson had material contact may be capable of enforcement. A 12-month worldwide ban on working for any competitor, imposed on a junior employee, is far less likely to be upheld. There is no universally safe duration. What is reasonable in one business or role may be excessive in another.
Check the contract before alleging a breach
Before confronting a former employee or their new employer, review the contract in force when employment ended. Employees are sometimes promoted without signing updated terms, or their contracts contain inconsistent versions of post-termination restrictions. A clause in an old offer letter may not reflect the employee’s final role or responsibilities.
Read the wording closely. Does the clause prohibit solicitation, dealing, employment by a competitor, or disclosure of information? Who falls within the definition of a restricted client or restricted employee? Is the relevant period measured from termination of employment or from the end of garden leave? These details can decide whether a threatened action is proportionate and legally sound.
It is also sensible to check whether the employer has complied with its own contractual obligations. A serious repudiatory breach by the employer may, in some circumstances, affect its ability to rely on post-termination restrictions. This requires careful legal analysis and should not be assumed.
Preserve evidence and act proportionately
Speed matters, especially where client approaches or confidential material are involved. However, an employer should not make allegations it cannot support. Preserve relevant evidence before it is lost, altered or circulated further. This may include resignation correspondence, customer messages, call records, CRM activity, access logs, company-device data and copies of documents lawfully retained by the business.
The investigation must respect data protection obligations and workplace privacy rules. Do not access a former employee’s personal accounts or devices without a clear legal basis. Evidence obtained improperly can create a separate problem and weaken the employer’s position.
The commercial objective should guide the response. If the immediate concern is a client list held by a former employee, the priority may be obtaining confirmation that it has been deleted and not used. If a key team is being approached, preserving evidence of contact and preventing further solicitation may be more urgent than pursuing damages at the outset.
How to enforce restrictive covenants in practice
Enforcement often begins with a focused letter before action. The letter should identify the relevant contractual terms, explain the conduct said to breach them, set out the evidence available, and state the action required. Depending on the circumstances, this may include stopping contact with named clients, returning or deleting documents, preserving relevant records, or providing written undertakings.
Undertakings are voluntary promises that can avoid the expense and disruption of court proceedings. They need to be drafted precisely. An undertaking that is too broad may be resisted; one that fails to cover the real risk may offer little protection. It may also be appropriate to write to the new employer, particularly where it may be receiving or benefiting from confidential information. The approach should remain factual and measured, rather than accusatory.
If the risk is urgent and undertakings are refused, an employer may consider applying to the High Court for an interim injunction. An injunction can require a former employee to stop specified conduct while the dispute is determined. It is a serious remedy, not a tactical threat. The court will consider the strength of the claim, whether damages would be an adequate remedy, the balance of convenience, delay, and whether the employer is prepared to give a cross-undertaking in damages if the injunction later proves unjustified.
Claims for breach of contract, damages and misuse of confidential information may also be available. The appropriate court and procedure depend on the claim and its value. Employment tribunals do not generally determine post-termination restrictive covenant disputes, so employers should not assume that a tribunal claim is the correct route.
Confidential information may provide separate protection
A weak or absent non-compete clause does not mean an employer has no remedy. Employees remain subject to duties concerning trade secrets and genuinely confidential information. During employment, their implied duties are generally wider. After employment ends, the focus is on information that has the necessary quality of confidence, rather than general skill, experience or knowledge acquired in the role.
The distinction matters. A former employee cannot usually be prevented from using their own professional expertise, remembering general market information, or working in a competing industry. They may, however, be restrained from using a confidential pricing strategy, an unreleased product plan, detailed customer data or trade secrets.
Clear contractual definitions, sensible information controls and regular confidentiality reminders make enforcement easier. They also reduce the need to rely on an overbroad non-compete clause.
Avoid common enforcement mistakes
The most frequent error is waiting too long. Delay can suggest that the risk is not genuinely urgent and can make an injunction harder to obtain. Another is treating every client move as unlawful. Clients are free to choose their suppliers, and contact initiated by a client may not amount to solicitation, depending on the clause and facts.
Employers should also avoid trying to rewrite a poor covenant through correspondence. Courts will not generally improve an unreasonable restriction to make it enforceable. In limited circumstances, clearly severable wording may be removed, but this is not a substitute for careful drafting.
A final mistake is overlooking the wider employment relationship. Garden leave, notice provisions, handover arrangements, bonus terms and settlement negotiations can all affect the best strategy. In some cases, a negotiated exit with tailored protections is more effective than litigation after the employee has left.
For employees facing a restrictive covenant claim
If you receive a letter alleging a breach, do not ignore it or assume the clause is automatically invalid. Keep relevant communications and documents, avoid deleting material, and obtain advice promptly. The wording of the restriction, your actual conduct and the information you hold will all be relevant.
You should be particularly cautious before contacting former clients or colleagues, transferring data, or beginning work on a competing account. A new employer may also need clarity about the restrictions before you start, as a dispute can affect both your role and the business hiring you.
Restrictive covenant disputes are often decided by detail, timing and evidence rather than broad statements about fairness. Clear legal advice at an early stage can help employers protect legitimate interests without overreaching, and help employees understand the limits of what a former employer can lawfully enforce.