In other situations, an alcohol policy might state that reporting to work under the influence of alcohol is serious misconduct. A hungover employee is still influenced by the alcohol in their system. They should not be at work in that state.
An employer must comply with its policy and investigate if the employee falls within the relevant definition. But what if you do not have a policy?
Parliament did not include a definition of "sick" in the Holidays Act 2003. When the Court of Appeal was last asked to define the meaning of "sick", it held that "sick" means "unfitness for health reasons of any nature and however caused".
Following this reasoning, self-induced sickness such as a hangover would provide a legitimate reason for an employee to claim sick leave. Your employee may even admit to you they are hungover, without comeback. What they cannot do is say they are ill "with the flu" or "suffering from a stomach bug".
Lying to one's employer is an act of misconduct, which could form the basis for disciplinary action and might even justify dismissal.
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