Employee Working for a Competitor: What Can a UK Employer Do?

Discovering that an employee may be working for a competitor can raise serious concerns. The arrangement might involve a formal second job, freelance assignments, consultancy work, helping a competing business informally or even operating a separate company that serves the same market.

However, an employee having two jobs does not automatically mean they have done anything wrong. Employers need to distinguish legitimate secondary employment from activity that conflicts with the employee’s contractual obligations, competes directly with the business or puts confidential information and customer relationships at risk.

Where there is a credible concern, an employer may investigate. In appropriate cases, a private investigator can help establish whether the suspected competitor activity is actually taking place. The investigation still needs to be lawful, necessary and proportionate, particularly where surveillance or personal information is involved.

This article looks at what employers in England can do if they suspect an employee is working for a competitor, what evidence may be relevant and where the legal limits lie. It reflects the law and official guidance available as at July 2026.

Can an Employee Work for a Competitor While Still Employed?

An employee is not generally prohibited from having a second source of income simply because they already have a job. Someone might work evenings in another industry, carry out occasional freelance work or have a completely unrelated part-time job.

The position becomes more serious when that additional work competes with their existing employer.

Acas explains that employees owe their employer an implied duty of fidelity, sometimes described as a duty of good faith. This requires employees to behave honestly and faithfully towards their employer. Acas specifically states that employees must not work in competition with their employer or improperly share confidential information obtained through their employment.^[1]

This duty exists as part of the employment relationship even if the employment contract does not contain a detailed clause expressly saying that the employee cannot work for a competitor.

That does not mean that every connection with a rival business will automatically amount to misconduct. The facts still matter. An employee doing occasional weekend work in a completely separate role may create very different issues from a senior salesperson secretly advising a direct competitor and dealing with customers in the same market.

What Could Working for a Competitor Look Like?

Competitor activity is not always a second PAYE job that appears neatly on a CV. Businesses sometimes become concerned about arrangements that are deliberately kept informal or structured through another entity.

Examples might include:

• An employee taking paid shifts or a part-time position with a direct competitor.
• A salesperson carrying out freelance or consultancy assignments for a competing firm.
• An employee operating their own limited company or sole trader business in the same market.
• A member of staff helping a competitor prepare quotations, tenders or proposals.
• An employee carrying out work for existing customers independently and retaining the income.
• A senior employee advising another business on pricing, suppliers, strategy or commercial opportunities.
• An employee introducing customers or prospects to a competitor.
• A member of staff performing competing work during hours when they are supposed to be working for their main employer.

The seriousness of each situation depends on the employee’s role, contractual terms, what the competing activity involves and whether the original employer’s commercial interests have actually been put at risk.

A Second Job Is Not the Same as Competing With Your Employer

This distinction is particularly important when dealing with an employee working two jobs.

Acas states that the duty of fidelity does not prevent employees from taking additional work for another employer generally. Problems can arise where the additional work is in competition with the original employer or is detrimental to that employer.^[1]

For example, an accountant employed by a construction company who works several evenings each week in a restaurant is unlikely to be competing with the construction business. The same accountant secretly providing financial consultancy to one of the company’s direct competitors may raise very different concerns.

The question for the employer is therefore not simply, “Does this employee have another job?” It is more useful to ask, “What are they doing, who are they doing it for and does that activity conflict with the obligations they owe us?”

Check the Employment Contract and Company Policies

Before commissioning an external investigation or beginning disciplinary action, employers should examine the documents governing the employment relationship.

The employment contract may contain a clause requiring employees to disclose secondary employment or obtain permission before undertaking outside work. Other relevant provisions might cover conflicts of interest, confidentiality, intellectual property, use of company equipment, working hours, customer solicitation and the employee’s obligation to devote their working time to the business.

Acas describes clauses preventing somebody from working for another employer, or requiring consent before doing so, as exclusivity clauses.^[2]

Employers should not automatically assume that every exclusivity clause is enforceable. Acas confirms that such clauses are prohibited for zero-hours workers and workers whose average weekly income is at or below the statutory Lower Earnings Limit, which was £129 per week in the guidance updated on 1 July 2026.^[2]

Those protections can affect whether an employer can take action simply because an employee has another job. Separate concerns about direct competition, confidential information or dishonest conduct may raise different issues, so employers dealing with a potentially serious breach should consider obtaining employment law advice.

What About Non-Compete Clauses?

Non-compete clauses are often discussed when employees join competing businesses, but there is an important distinction between competition during employment and restrictions that apply after somebody leaves.

A traditional restrictive covenant or non-compete clause usually seeks to restrict particular activities after employment ends. Acas advises that post-employment restrictions need to be clear and specific, and their enforceability can be a complex legal question.^[2]

If the employee is still employed, the employer should also consider their existing contractual obligations and the implied duty of fidelity. An employer therefore does not necessarily need to wait until somebody resigns before concerns about active competition become relevant.

Could Working Two Jobs Create a Working Time Problem?

Secondary employment can also create issues even where the second employer is not a competitor.

Under the Working Time Regulations 1998, most adult workers should not work more than an average of 48 hours per week unless they have voluntarily opted out or an applicable exception applies. GOV.UK confirms that where someone has more than one job, their combined working hours should normally remain within the 48-hour average.^[3]

This can become important where an undisclosed second job leaves the employee regularly exhausted, creates health and safety concerns or affects their ability to carry out their main role safely.

It is another reason why employers should avoid treating all secondary employment as a simple competition issue. Sometimes the genuine concern may instead relate to safety, availability, performance or working hours.

What Evidence Should an Employer Look for First?

Suspicion should normally be tested against information the employer already lawfully holds before more intrusive investigative measures are considered.

For example, the employer might review the employee’s contract, conflict declarations, working patterns, timesheets, expense claims, customer complaints or information supplied by managers and colleagues. Relevant company records may also include authorised access logs, document histories or other business information where its use is permitted and compliant with data protection requirements.

If the concern is that an employee is operating their own competing company, publicly available Companies House records may establish whether they are a director or person with significant control of another business. A competing company’s website, professional profile or openly published advertising may also contain relevant information.

Employers should distinguish between evidence and inference. Seeing that an employee is listed as a director of another company may justify further questions, but it does not necessarily prove that the business actively competes with the employer or that the employee has breached their duties.

When Might a Private Investigator Help?

A private investigator may be useful where there is a specific and credible allegation that cannot reasonably be established through internal records alone.

For example, the employer may have information suggesting that a member of staff regularly attends a competitor’s premises on particular days, carries out work for customers that should belong to the employer or operates an undeclared competing business away from the workplace.

At SPS Investigations, we provide corporate investigation services for businesses across London and the Home Counties. Where an employer has a legitimate concern about undeclared competitor activity, we can help establish what evidence would actually answer the employer’s question and whether external enquiries are proportionate.

Our role is to establish relevant facts rather than to assume that an employee has done something wrong.

What Can a Private Investigator Lawfully Establish?

The appropriate method depends on what is suspected and how serious the potential misconduct is.

Lawful open-source enquiries might establish whether an employee is publicly connected with another company, advertises competing services, appears on a competing company’s website or operates another commercial venture.

Where surveillance is properly justified, an investigator may in appropriate circumstances observe activity visible from public places or other locations they are lawfully entitled to use. This might help establish whether an employee attends a competitor’s premises, carries out apparent work there, makes business-related journeys or meets relevant individuals in public.

Reports can document dates, times, locations, movements and relevant activity, supported by photographs or video where lawfully and proportionately obtained.

The resulting evidence may answer quite a narrow question. For example, an employer may need to establish whether an employee who claims to have no involvement with a particular company actually attends its premises repeatedly and spends substantial periods there.

That evidence still needs context. An investigator should report what was observed rather than state that the employee has committed gross misconduct simply because they were seen entering another company’s premises.

Covert Surveillance of Employees Requires Particular Care

An employer cannot assume that suspected competitor activity automatically justifies following an employee for days or monitoring their private life.

The Information Commissioner’s Office states that covert worker monitoring is unlikely to be justifiable in most ordinary circumstances. It may potentially be justified in exceptional cases where it is necessary to prevent or detect suspected criminal activity or an equivalent issue such as gross misconduct.^[4]

The ICO says covert monitoring should be authorised at senior management level, supported by a data protection impact assessment, directed towards a specific suspicion and limited to the shortest reasonable timeframe. Monitoring should stop when the investigation is complete.^[4]

If a private investigator is instructed to undertake covert monitoring, the ICO also states that the employer should have an appropriate contract requiring the investigator to collect information in a way that meets the employer’s data protection obligations.^[4]

The employer therefore remains responsible for considering why the investigation is necessary, what personal information may be collected and whether a less intrusive way of resolving the issue is available.

What an Employer or Investigator Should Not Do

Suspecting serious misconduct does not create a right to access somebody’s private digital life.

An employer should not attempt to obtain passwords, log into an employee’s personal email, access private social media accounts, read WhatsApp messages from a personal device, obtain private banking information or circumvent security controls simply because the information could be useful to the investigation.

Section 1 of the Computer Misuse Act 1990 creates an offence relating to unauthorised access to computer material.^[7] Separately, section 170 of the Data Protection Act 2018 makes it an offence, subject to statutory defences, knowingly or recklessly to obtain or disclose personal data without the consent of the controller.^[8]

Private investigators do not have special powers that allow them to bypass these restrictions. We cannot hack accounts, intercept private communications or obtain confidential records simply because an employer has instructed us.

What About the Employee’s Work Email or Company Laptop?

Company-owned systems require a more nuanced approach.

The fact that an employer owns a laptop, telephone or email system does not automatically give unrestricted permission to inspect everything stored or communicated through it. Worker monitoring remains subject to data protection law, including requirements around purpose, necessity, fairness, transparency and data minimisation.^[4]

Existing IT, email and monitoring policies will be relevant. Employers should consider what workers have previously been told, what information is genuinely necessary for the investigation and whether personal or sensitive communications are likely to be captured.

The ICO specifically warns that covert monitoring should not, in most circumstances, capture communications workers would reasonably expect to remain private, such as personal emails.^[4]

Where reviewing workplace communications forms an important part of a serious investigation, involving the organisation’s data protection officer, HR adviser or employment solicitor before accessing the material may reduce unnecessary legal risk.

How Should an Employer Investigate Suspected Competitor Work?

A structured investigation is usually safer than confronting the employee immediately or commissioning open-ended surveillance.

1. Define the concern. Record what the employee is suspected of doing, which competitor is involved and why the activity could harm the business.
2. Review the contractual position. Check the employment contract, secondary-employment provisions, confidentiality terms and conflict-of-interest policies.
3. Preserve relevant internal evidence. Retain appropriate records before they are routinely deleted, while ensuring that access to personal information remains authorised and proportionate.
4. Consider less intrusive enquiries first. Public company information, business websites and internal records may answer some questions without surveillance.
5. Assess data protection implications. Establish an appropriate lawful basis and consider whether a DPIA is required, particularly before covert monitoring.
6. Set a narrow external investigation brief where necessary. Define the dates, locations, behaviour and questions that the investigator is being asked to establish.
7. Give the employee an opportunity to respond. Evidence gathered externally should normally form part of a fair workplace investigation rather than being treated as an automatic finding of guilt.

Evidence Should Test the Allegation, Not Just Support It

One of the risks in competitor investigations is confirmation bias. Once a director or manager believes an employee is secretly assisting a rival, almost any unusual activity can start to appear suspicious.

A properly conducted investigation should be capable of disproving the allegation as well as supporting it.

For example, surveillance may confirm that an employee visits premises occupied by a competitor. Further context may reveal that several unrelated businesses operate from the same site, or that the employee had a legitimate reason to be there.

Similarly, a professional networking profile showing a historical connection with a competitor does not necessarily prove current employment.

Reliable evidence should therefore record what was actually established and identify any important limitations rather than presenting assumptions as facts.

What Happens If the Evidence Confirms the Employee Works for a Competitor?

The next step depends on the seriousness of the conduct, the employee’s contract and workplace policies.

The fact that an employee works for a competitor may support allegations involving breach of contract, breach of the duty of fidelity, conflict of interest, misuse of confidential information or dishonesty. More serious cases could potentially amount to gross misconduct, but employers should not assume that dismissal without notice automatically follows.

Acas guidance requires employers to carry out an appropriate investigation before making disciplinary decisions. The purpose of the investigation is to establish the facts and determine whether there is a case to answer.^[5]

If there is a disciplinary case, the employee should normally be told the allegations and relevant evidence and be given an opportunity to respond. The Acas Code of Practice provides the minimum framework employers should follow when dealing with disciplinary matters.^[6]

An explanation from the employee may materially change the situation. The competing activity might have been authorised by a previous manager, may fall outside the actual scope of the employer’s business or may not have occurred in the way initially suspected.

Could Working for a Competitor Amount to Gross Misconduct?

Potentially, but the classification depends on the circumstances.

A senior employee deliberately diverting customers to a business they secretly own, supplying confidential pricing information to a competitor or performing competing paid work during their employer’s working hours could be viewed very differently from an employee who innocently takes unrelated secondary employment without realising they should have notified HR.

The employer should consider the employee’s role, seniority, contractual obligations, the degree of competition, whether conduct was concealed, whether confidential information was involved and whether the employer suffered or was exposed to commercial harm.

Where dismissal, an injunction or other legal proceedings are being contemplated, obtaining advice from an employment solicitor before acting on the investigation report may be particularly important.

Can an Employer Suspend the Employee While Investigating?

Suspension is possible in some investigations, but it should not be an automatic reaction.

An employer may consider temporary suspension where there is a genuine risk to confidential information, evidence, customers, systems or colleagues. Less restrictive alternatives may sometimes be available, such as temporarily removing access to particular systems, accounts or commercially sensitive projects.

Suspension should not be treated as proof that misconduct has occurred. The employer should follow its own policies and current Acas guidance and keep any suspension under review.

Using a Private Investigator to Establish the Facts

Cases involving working for a competitor while employed can be difficult because employers often receive fragments of information rather than clear evidence. A customer may mention seeing the employee working elsewhere, a director may discover an unfamiliar company connection or another member of staff may report that the employee is carrying out private work for clients.

The objective should not be to investigate every aspect of the employee’s personal life. It should be to answer a defined commercial question using the least intrusive reasonable method.

At SPS Investigations, we can discuss the evidence already available and whether discreet external enquiries are likely to add anything useful. Depending on the circumstances, our corporate investigations may involve lawful open-source research, public-place observations and clear factual reporting.

We work with businesses in London and throughout the Home Counties. Where HR advisers, employment solicitors or data protection professionals are already involved, we can work to a clearly defined investigative brief so that the evidence-gathering stage supports the wider employment process.

We will not recommend unlawful access to private accounts, unrestricted surveillance or speculative monitoring designed simply to uncover something damaging about an employee.

If you have a genuine concern that an employee is secretly working for, advising or assisting a competitor, you can contact SPS Investigations for a confidential discussion about the circumstances and whether an external investigation would be appropriate.

Frequently Asked Questions

Can an employee legally work for a competitor in the UK?

Employees owe their employer an implied duty of fidelity. Acas states that this includes not working in competition with their employer. Whether particular secondary work amounts to a breach will depend on the nature of the activity, the employee’s contractual obligations and the circumstances.

Can an employee have two jobs at the same time?

Yes. Having two jobs is not automatically unlawful or a breach of an employment contract. Problems can arise where a second job competes with the employer, breaches contractual terms, affects performance or creates working-time and health and safety concerns.

Does an employee have to tell their employer about a second job?

It depends on their contract and workplace policies. Some contracts require employees to disclose secondary work or obtain permission. Employers should check the contractual wording before assuming non-disclosure itself amounts to misconduct.

Can an employer hire a private investigator if an employee works for a competitor?

Potentially. There should be a legitimate and specific concern, and the methods used must be lawful, necessary and proportionate. Covert employee monitoring requires particular care under data protection law and ICO guidance.

Can a private investigator follow an employee to another workplace?

Targeted observations in public places may sometimes be possible where the investigation is properly justified. Surveillance should not involve trespass, intrusion into genuinely private areas or unrestricted monitoring of the person’s private life. Covert worker monitoring should normally be reserved for exceptional circumstances.

Can an employer check Companies House to see whether an employee runs another business?

Yes, publicly available Companies House information may form part of a legitimate investigation. Records can help establish company directorships, persons with significant control and other filed information. The employer should still interpret the information carefully because a company connection does not by itself prove misconduct.

Can an employer access an employee’s personal email or WhatsApp messages?

An employer should not access private accounts or personal devices without lawful authority. Unauthorised computer access and unlawful obtaining of personal data can give rise to criminal and data protection issues. Company-owned systems have a different legal context but must still be handled in accordance with data protection law and relevant workplace policies.

Can an employee be dismissed for secretly working for a competitor?

Potentially. Direct competition, dishonesty, conflicts of interest or misuse of confidential information may amount to serious misconduct. However, dismissal is not automatic. The employer should investigate the facts, consider the contract and policies and follow a fair disciplinary procedure in accordance with the Acas Code.

This article provides general information about employment investigations in England and reflects the law and official guidance available as at July 2026. It is not a substitute for advice from an employment solicitor, HR professional or data protection adviser about a specific case.