Supreme Court clarifies the law on part-time worker discrimination claims

The Supreme Court has ruled today in Augustine v Data Cars Limited giving clarity on when part-time workers can claim discrimination. The question was whether they had to show that the reason for their treatment was solely or mainly because they were part-time, or whether being part-time only needed to be a 'significant, substantial or effective cause' for that treatment.

Case Background

The case involved a private hire cab driver who worked fewer hours per week than some of his colleagues but had to pay the same 'access fee' of £148 per week as those working up to twice as long as he did, meaning he suffered a bigger 'bite' out of his take-home pay than his full-time colleagues.

It was argued that the reason Mr Augustine was charged the same fee as full-time drivers was not because he was part-time, but because the employer wanted to make money from all the drivers, and his being part-time wasn't the sole reason he was charged the fee, so it wasn't part-time worker discrimination. This didn't stand up to scrutiny.

Supreme Court’s Decision

The Supreme Court held (in a rather complicated judgment that wades through a lot of conflicting earlier decisions) that the proper test for deciding whether there is part-time worker discrimination is whether being part-time was an effective cause, i.e. part of the reason why the worker is treated less favourably than a full-time worker, even if there is another more important reason for the treatment, it is still part-time worker discrimination.

This brings part-time worker discrimination closer in line with other types of discrimination claims and makes such claims harder for employers to defend.

What this means in practice

Part‑time worker discrimination applies to workers, including:

• Employees
• Individuals who personally perform labour but are not running their own business, such as hairdressers on chair‑rental agreements or private hire drivers paying fees to operate under a taxi firm's brand.

Part‑timers can only compare themselves with full‑timers:

• Working under the same type of contract
• Doing the same or broadly similar work
• With similar skills, experience or qualifications

Employers may justify different treatment, but only if it is objectively justified.

Why the Fee Was Discriminatory

Charging part‑timers the same fixed weekly fee as full‑timers was less favourable because it reduced a larger proportion of Mr Augustine’s pay. Employers who impose fixed costs or provide benefits only to full‑time staff should review their arrangements to ensure compliance.

Next Steps for Employers

• Review fixed fees for part‑timers
• Assess benefit structures
• Check objective justification
• Audit part‑time arrangements

Full judgment: https://supremecourt.uk/uploads/uksc_2025_0122_judgment_f8eb0f1fbd.pdf

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