Also known as polygamous working, moonlighting is no longer an edge case. New research suggests it's quietly becoming the norm and the hiring process is often the first line of defence employers are failing to use.
Moonlighting and polygamous working have long been treated as background noise in the world of HR, an uncomfortable topic that rarely made it to the boardroom agenda. An employee quietly picking up extra work, a candidate stretching the truth on their CV. Difficult to prove, easier to ignore.
But the cost of that inaction is becoming impossible to dismiss.
Fresh research from Cifas, the UK's leading fraud prevention service, reveals that workplace fraud has moved well beyond isolated incidents. It's becoming normalised and in some cases, it's being carried out by the very leaders who should be setting the cultural tone.
Cifas surveyed 2,000 UK employees across sectors including HR, finance, IT, and engineering for its Workplace Fraud Trends report. The findings are striking.
1 in 5 UK professionals (19%) admit to secretly working two competing jobs simultaneously, a practice known as "polygamous working", and almost a quarter (24%) consider this behaviour entirely justifiable.
This isn't a niche issue confined to junior employees either. A staggering 88% of business owners and 70% of C-suite executives said that certain unlawful workplace behaviours are justifiable. When the people setting the rules consider them optional, the culture of a business is under serious threat.
The data also reveals a troubling picture around the hiring process itself:
As Mike Haley, CEO of Cifas, put it: "These insights suggest a shift in workplace norms and raise urgent questions about organisational culture, risk management, and accountability."
The sharp rise in polygamous working is not happening in a vacuum. It's the product of converging pressures that have fundamentally changed the employment landscape.
Remote and hybrid working, accelerated by the pandemic, has made it far easier for employees to hold multiple roles without detection. When no one can see whether you're on a call for employer A or employer B, the practical barriers to dual employment all but disappear.
At the same time, the cost-of-living crisis has made the financial temptation very real. Research by Utility Warehouse found that over one-third of UK adults now manage multiple income streams, a figure that was projected to approach half the adult population by 2025. Rising costs and stagnant wages have made the financial incentive very real, and the shift to remote working has removed many of the practical barriers that once made dual employment difficult to sustain. The result is a growing cohort of employees holding multiple roles simultaneously, often in direct breach of their contracts and without either employer's knowledge.
The concern for employers isn't simply a matter of productivity. When an employee is secretly working for a competitor, the risks extend to data security, intellectual property, conflicts of interest, and reputational damage. As employment lawyers have noted, if a second job is in the same or an adjacent industry, confidential information could easily find its way to a secondary employer.
A National Fraud Initiative report uncovered 23 instances of council staff working multiple jobs simultaneously, resulting in £500,000 in overpaid salaries. High-profile cases have involved civil servants holding three full-time government roles at once. The problem isn't hypothetical, it's already costing organisations real money.
Alongside moonlighting, the Cifas data shines a light on an equally serious problem: candidates fabricating their employment histories to get through the door in the first place.
Reference houses, organisations that provide fake employment references for a fee are now a recognised and growing threat. These aren't amateur operations. Many register legitimate-looking companies, build convincing websites, and create contact details that pass a cursory check. For a few hundred pounds, a candidate can manufacture years of experience they never had.
The consequences go beyond a bad hire. In some documented cases, individuals who used reference houses were later coerced into committing fraud against their new employer by the same criminal networks that provided the fake credentials. What looks like a candidate hiding an employment gap can sometimes be something far more sinister.
AI is adding another layer of complexity. Employers are increasingly encountering AI-generated CVs, deepfake video interviews, and algorithmically optimised applications that mask the truth. The old tells are disappearing and the traditional reference check, already a flawed process, is becoming even less reliable as a standalone safeguard.
Most employers still rely on candidate-supplied references and CV declarations to verify employment history. But if the Cifas data tells us anything, it's that a significant portion of candidates are either misrepresenting their backgrounds or know someone who has and the fraudulent infrastructure to support this is well-established and accessible.
Chasing previous employers for written references is slow, inconsistent, and easily manipulated. A phone number that routes to a reference house is indistinguishable from a legitimate HR contact. An email from a plausible-sounding domain can sail past even experienced recruiters.
The question organisations should be asking isn't "do we check employment history?" It's "are the checks we're doing actually reliable?"
This is where verified, source-direct employment data changes the picture entirely.
At Giant Screening, our Instant Activity Verification service retrieves employment history directly from HMRC, the UK's national tax authority, in real time. Because the data comes straight from source, it removes the possibility of falsified references, fabricated employer details, or coached declarations.
In seconds, not days, you receive verified employer names, employment dates, PAYE reference numbers, and optional income and tax data, covering up to five years of activity. Any gaps or discrepancies between what a candidate has declared and what HMRC holds on record are surfaced immediately, before a decision is made.
There are no employers to chase, no reference letters to scrutinise for suspicious formatting, and no risk of a reference house slipping through. The data is bank-grade encrypted, fully GDPR compliant, and always consent-based, meaning the candidate experience remains smooth and drop-off rates stay low.
In a hiring landscape where Cifas is recording record levels of fraud risk cases, over 217,000 filings in the first half of 2025 alone, the ability to verify employment history at source isn't only a nice-to-have. It's essential due diligence.
Moonlighting, reference fraud, and polygamous working are no longer fringe concerns. They are measurable, growing, and in many cases considered acceptable by the very people committing them. Employers who rely on traditional screening methods are increasingly operating blind.
The good news is that the solution doesn't have to be complicated, slow, or invasive. Verified employment data, drawn directly from HMRC, gives you the confidence to hire with clarity, close gaps before they become liabilities, and build a workforce you can actually trust.
Want to find out how Instant Activity Verification works for your hiring process? click on speak to a screening expert below: