Deception Dilemma: A Second Job in the UK Might Lead to Trouble

Having a second job, known as moonlighting, is not illegal in the U.K. However, while in the past someone might work 9 to 5 in an office and then work in a pub in the evenings, there is an increasing trend for individuals to hold two supposedly full-time jobs, receive two full-time salaries, but not fulfill their contractual obligations to either employer. This is known as “polygamous working.” Employees who work two full-time jobs are (unsurprisingly) usually not working their contracted hours and splitting their time between both roles. 

With the rise of remote work post-pandemic, it has become easier for employees to work multiple jobs without detection. Many people are drawn to the idea of a second income, especially during a cost-of-living crisis. Social media influencers often promote such practices as a means of increasing income, and advice circulating on how to manage dual roles only compounds the problem.

What social media may often overlook is that deliberately concealing dual, simultaneous employment can amount to fraud. The National Fraud Initiative (NFI) is part of the Public Sector Fraud Authority’s data and analytics service. Through the data it receives from 1,100 participating public-sector and private-sector organizations, it identifies potential cases of polygamous working. In a recent pilot scheme in London, looking specifically at permanent employees as well as people employed through agencies, the NFI identified 23 polygamous workers, resulting in overpaid salaries totaling around 500,000 pounds. In perhaps the most extreme example, the NFI uncovered an individual who had held three roles in three government departments during two separate time frames, having withheld his civil service employment history during the application process for the second and third roles.

The consequences of working a second job can be grave. Individuals stretching themselves across two full-time roles pose the risk that they are not performing either role adequately, which has huge potential consequences if the employee holds critical safety responsibilities.

Employers also have responsibilities under the Working Time Regulations, which protect workers by putting limits on work hours and ensuring appropriate breaks. In the absence of a signed opt-out agreement, employers must make sure that workers do not work more than the statutory limit of 48 hours a week on average. It is not possible for employers to do so, or to maintain accurate records as required, if they are unaware that an employee is working another job. Breaching the 48-hour working week can result in serious repercussions such as:

• Legal penalties and potentially unlimited fines for employers.
• Potential damages or claims for compensation if breaches of the regulations lead to adverse effects on employees’ health and well-being.
• Health and safety risks.

Employers will also be concerned about the potential for breaches of confidentiality, particularly when the employee is working for a competitor.

If an employer discovers deception, a polygamous employee also faces significant personal and financial consequences in terms of the repayment of overpaid wages and cost contributions, as well as even potential imprisonment.

How to Spot Polygamous Working

There are some signs of polygamous working. You may notice that an employee’s performance and engagement has started to decline, especially if they were previously a top performer. You can also watch for frequent absences or decreased availability for meetings, which could indicate commitments elsewhere. Employees juggling two jobs may have disproportionate levels of stress or fatigue in response to what is considered a reasonable workload. There could, of course, be other reasons for these types of issues, but employers should bear in mind the possibility of polygamous working when they are discussing their concerns with the employee.

Side Note on Side Hustles

Side hustles are also increasingly common in the modern labor market, particularly among younger workers. Side hustles are not the same as polygamous working, with the worker normally carrying out a side hustle during their free time in the evenings and during weekends. They can, however, lead to some of the same issues, such as a detrimental impact on performance or confidentiality concerns, and there is also a risk of a side hustle spilling into the employee’s contracted hours.

Key Steps for Employers

So, how can employers protect themselves from polygamous working, both in terms of prevention and responding if they uncover a polygamous worker?

• Ensure pre-employment screening processes are comprehensive, including references from the candidate’s previous employer.
• Check your offer letters and make sure they clearly state the company’s position on second jobs.
• It is standard for employment contracts to require the employee to devote their whole time and attention to their role during their contracted hours. If you have one, draw attention to your anti-fraud policy.
• Ensure there is no ambiguity around what you expect of an employee and their dedication to the role they have been offered. Often, employment contracts will specifically require an employee to disclose a second job to their employer or prohibit working a second job by including an exclusivity clause in the employment contract. An exclusivity clause will be valid only if the employee earns more than the lower earnings limit. Exclusivity clauses will be void in the contract of someone on a zero-hours contract or earning below the lower earnings limit.
• Make sure the contract contains obligations preventing an employee from disclosing confidential information and protecting intellectual property. This is important for managing the risks associated with employees’ side hustles as well as polygamous working.
• If an employee tells you about a side hustle, have an open-minded conversation about how to manage this. You should, of course, remind them of their contractual obligations regarding confidentiality, intellectual property, and potential conflicts of interest. You should also point out your health and safety responsibilities as an employer and the limits on work time, as well as encourage an ongoing dialogue to help you manage any concerns around performance or stress levels.
• If you suspect that an employee is working polygamously, review the obligations within their contract. Start with an open conversation and, if you find evidence of polygamous working, seek to understand why the employee is doing so. When it comes to disciplinary action, you may wish to differentiate between simple dishonesty or greed and a situation in which an employee is desperate due to their financial or personal situation.
• Using monitoring tools might seem like an obvious solution to combat polygamous working, but they bring their own challenges, including data protection compliance and employee expectations of privacy.

Helena Rozman and Sarah Beeby are attorneys with Dentons in Milton Keynes, U.K.  © 2025 Dentons. All rights reserved. Reposted with permission of Lexology.