Supreme Court clarifies the test for part-time worker discrimination claims
Part-time workers have the right not to be treated less favourably on the grounds of their part-time status than comparable full-time employees. The recent Supreme Court case of Augustine v Data Cars Limited clarifies the scope of this protection, holding that where a worker’s part-time status is an “effective cause”, treatment will be “on the ground of” their part-time status for these purposes.
With around a quarter of the UK workforce working part-time, this is a significant decision with potentially wide ramifications for employers.
The decision
A part-time workers have the right not to be treated less favourably than a comparable full-time worker on the ground of their part-time status, unless the treatment is objectively justified. Pro-rating a part-time worker’s pay or benefits by reference to the proportion of full-time hours worked does not constitute less favourable treatment for these purposes.
Prior to this Supreme Court decision, the correct test for causation – the meaning of ‘on the ground of part time status for these purposes – was unclear. Diverging decisions in different cases set the test as, on the one hand, requiring part-time status to be the sole cause of the treatment and, on the other hand, requiring it to be merely an ‘effective cause’.
Called upon to resolve this issue, the Supreme Court held that the correct test to establish causation was whether the worker’s part-time status was an ‘effective cause’ of the treatment. This brings the test in line with the causation test applicable in discrimination cases under the Equality Act 2010, and means that for causation to be established, a worker’s part-time status need not be the sole, or even the main, cause of any less favourable treatment – it is sufficient for it to be a significant influence.
The decision significantly lowers the bar for establishing causation, with the result that, going forward, the battleground is likely to shift to questions of whether treatment is objectively justified. The Court expressly noted that where the reason for less favourable treatment is mixed and there are legitimate business reasons alongside a worker’s part-time status, that will be relevant to questions of causation.
Practical implications for employers
For HR professionals, the key takeaway is that policies and practices affecting pay, benefits, fees, allowances, bonuses and other working arrangements should be reviewed through the lens of their impact on part-time staff. Where pro-rating is not possible or practicable, employers should give careful thought to whether a solution that disadvantages part-time workers can be objectively justified – in other words, whether it is a proportionate means of achieving a legitimate aim. Employers should carefully document their reasoning to ensure that decisions are defensible in case of a challenge – noting also part-time workers’ right to request a written explanation for any less favourable treatment.
If you would like to discuss the implications of the decision for your business, please contact a member of the team for further advice.
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