Proving sickness fraud to the standard required for a defensible disciplinary dismissal is a specific and demanding evidential exercise. The employer must establish, on the balance of probabilities, that the employee was not genuinely incapacitated for work during the absence period claimed. That is a factual finding, not a legal technicality, and it requires evidence that is direct, contemporaneous, and capable of surviving the scrutiny of an employment tribunal.
In my experience, the cases that fail at tribunal are rarely those where the employer’s substantive concern was wrong. They are those where the concern was well-founded but the evidence gathered was insufficient, improperly obtained, or poorly presented in the disciplinary process. This article sets out what constitutes sufficient, properly obtained evidence and how it should be assembled into a case that holds up.
What Evidence Is Needed?
The standard of proof in employment tribunal proceedings is the balance of probabilities: the tribunal must be satisfied that it is more likely than not that the employer’s version of events is accurate. This is a lower standard than the criminal standard of beyond reasonable doubt, but it is not a low bar when the employee is able to put forward an account and challenge the employer’s evidence.
The employer needs evidence that is sufficient to satisfy the following test, derived from British Home Stores Ltd v Burchell: the employer genuinely believed that the employee was not genuinely absent for medical reasons; that belief was based on reasonable grounds; and it was formed after a reasonable investigation. The investigation must be thorough enough that the belief is reasonable, not merely the employer’s intuition.
The evidence categories most commonly relied upon in sickness fraud cases are surveillance evidence, social media evidence, witness evidence, and corporate or financial intelligence. In the most effective cases, multiple categories of evidence are combined, each corroborating the others and building a picture that is difficult for the employee to explain away.
Surveillance Evidence
Video surveillance evidence gathered by a professional investigator is the most direct and most persuasive form of evidence in a sickness fraud case. It captures, in real time, what the employee was actually doing during their absence — their physical capabilities, their location, their activities, and their conduct — and it does so in a form that is time-stamped, contemporaneous, and difficult to dispute.
For surveillance evidence to be admissible and persuasive, it must: have been gathered by a trained professional investigator operating within the applicable legal framework; be accompanied by a contemporaneous log that records the investigator’s observations as they were made; be preserved in its original, unedited form; and be presented with a witness statement from the investigator that is capable of being tested in tribunal proceedings if required.
The surveillance evidence is most effective when it shows the employee performing activities that are directly inconsistent with their reported condition. An employee with a back injury that prevents work who is observed carrying heavy equipment, engaging in sport, or performing sustained physical labour has provided the core of a compelling sickness fraud case. The footage does not need to show something dramatic. It needs to show something that is inconsistent with the reported incapacity in a way that the employee cannot credibly explain.
Witness Evidence
Witness evidence in sickness fraud cases typically comes from colleagues, neighbours, or other individuals who have observed the employee during the absence period and whose observations are inconsistent with the reported incapacity. This evidence is valuable corroboration of surveillance and social media findings but rarely sufficient on its own.
For witness evidence to be reliable and usable, it should be gathered in a structured interview, documented contemporaneously, and the witness should be willing to provide a statement and, if required, to give evidence at tribunal. Informal observations relayed through third parties, or accounts that the witness is reluctant to formalise, are less reliable and create procedural vulnerabilities in the disciplinary process.
Social Media Evidence
Social media evidence gathered during a sickness investigation must be preserved in a form that accurately represents what was publicly visible at the time it was gathered. Each item of evidence should be documented with: the platform and the specific URL or post identifier; the date and time of the post; the privacy settings visible at the time of gathering; and a clear description of what the content shows.
Screenshots alone are insufficient without this documentation because they can be dismissed as unverifiable. A professionally produced social media investigation report, using specialist preservation tools that capture metadata, timestamps, and privacy settings, provides evidence that is significantly more robust in disciplinary and tribunal proceedings than screenshots taken on a manager’s phone.
Building a Defensible Case
A defensible sickness fraud case is built from the combination of a thorough investigation, properly gathered evidence, a fair disciplinary process, and accurate documentation throughout. The elements that most commonly determine whether a case succeeds or fails at tribunal are:
Proportionality of the investigation: the investigation must be proportionate to the specific concern. Commissioning covert surveillance against an employee whose only indicator is a single Monday absence is unlikely to be defensible. Commissioning surveillance against an employee who has a chronic pattern of day-of-week absences and whose social media shows physical activities incompatible with their reported condition is proportionate and defensible.
Quality of the investigation: the investigation must be conducted by a professional investigator using documented methodology within the applicable legal framework. Evidence gathered informally or through methods that raise legal questions will face sustained challenge.
The disciplinary process: the ACAS Code must be followed. The employee must see the evidence and have a genuine opportunity to respond before any decision is made. The decision must be made by the appropriate level of management, with a right of appeal to a more senior or independent person. Shortcuts in the process create independent grounds for an unfair dismissal finding even where the evidence of fraud is strong.
Documentation: every stage of the investigation and disciplinary process must be documented contemporaneously. Decisions, observations, conversations, and evidence all need a paper trail. A case that is well-evidenced but poorly documented is more vulnerable than it should be.
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