UK Supreme Court Widens Part-Time Worker Discrimination Test
The UK Supreme Court has ruled that part-time workers only need to show their status was an 'effective cause' of less favourable treatment, not the 'sole reason', significantly lowering the bar for discrimination claims.
The UK Supreme Court has allowed an appeal in Augustine v Data Cars Ltd, significantly altering the causation test for discrimination under the Part-time Workers (Prevention of Less Favourable Treatment) Regulations 2000. Overturning a prior Court of Appeal decision, the court held that a claimant need only demonstrate that their part-time status was an 'effective cause' of the less favourable treatment, not the 'sole reason.' The justices reasoned that the UK's implementing regulations deliberately used the phrase 'on the ground that,' which aligns with established domestic discrimination law, rather than adopting the narrower 'solely' language from the corresponding EU Framework Agreement.
This decision materially lowers the bar for part-time workers bringing discrimination claims and increases litigation risk for employers. Company policies, such as flat-rate fees for benefits or access to systems, that were previously defensible may now be vulnerable if they disproportionately disadvantage part-time employees. Any UK employer with a part-time workforce is affected.
Sophisticated counsel should advise clients to immediately review all policies, pay scales, and benefit schemes to assess for potential disparate impacts on part-time staff. Any differential treatment must be objectively justified to mitigate the heightened risk of successful claims.