Equal pay and the material factor defence

The Employment Appeal Tribunal decision in Thandi and Others v Next Retail Ltd is a noteworthy addition to the growing body of case law on equal pay and the material factor defence. Although the judgment does not establish new legal principles, it provides helpful clarification on the relationship between market forces, objective justification and proportionality where employers seek to justify pay differences between groups undertaking work of equal value. 

In doing so, the EAT offers useful guidance on how tribunals should approach recruitment and retention arguments in equal pay claims, an issue likely to remain relevant in the context of ongoing retail sector litigation.

Clarification not change

Importantly, the EAT did not revisit the tribunal’s finding that retail employees and warehouse operatives were performing work of equal value. Nor did it disturb the conclusion that the relevant pay practices placed women at a particular disadvantage.

The appeal’s significance lay elsewhere. The EAT found that the tribunal had incorrectly characterised Next’s justification as concerned principally with cost, thereby distorting both the legitimate aim and proportionality analyses. 

The tribunal had effectively focused on Next’s ‘financial headroom’ and whether it could have afforded to increase pay for retail workers. The EAT held that this was the wrong question. The proper inquiry was whether paying warehouse employees more constituted a proportionate means of achieving a legitimate business objective, namely recruiting and retaining sufficient labour to maintain warehouse operations in a competitive market.

The decision therefore provides important clarification of equal pay principles. It reinforces that, where employers rely on a material factor defence, tribunals must focus on the rationale for the higher rate of pay rather than simply asking whether the lower-paid group could also have received the same benefit.

Market forces and objective justification

The most significant aspect of the judgment is the EAT’s treatment of market forces. European and domestic authorities have long recognised recruitment and retention considerations as capable of constituting a legitimate aim. However, the EAT’s reasoning may be seen as tempering some of the scepticism that market-based justifications have attracted in recent equal pay litigation. 

The judgment makes clear that labour market pressures, workforce planning and operational necessity can constitute legitimate aims in their own right. Tribunals should not automatically reduce such arguments to a simple cost-saving exercise. The key question remains whether the pay differential is a proportionate response to a genuine business need.

The ruling’s wider significance is that it draws a clearer distinction between employers responding to genuine market conditions and employers simply seeking to minimise labour costs. That distinction is likely to influence future equal pay claims, particularly where different workforce groups are affected by materially different recruitment and retention dynamics.

For retailers, this is potentially significant. Many equal pay claims involve retail and distribution employees whose roles are shaped by very different competitive and operational pressures. The EAT’s reasoning recognises that such differences may legitimately influence pay-setting decisions, provided any resulting disparity is unrelated to sex and can be objectively justified.

At the same time, the judgment falls well short of creating a market-forces exemption. Next’s appeal did not succeed in relation to every pay element, with findings on matters such as night-time pay, overtime and paid rest breaks remaining intact. The decision therefore reinforces that proportionality remains the central safeguard and that each element of a remuneration package must be justified on its own merits.

Evidence remains central

Perhaps the most important practical lesson from the judgment is that employers seeking to rely on market forces must be able to evidence their position.

The EAT did not suggest that employers need exhaustive economic analysis or highly technical labour market evidence. However, the decision should not be interpreted as permitting reliance on generic assertions about ‘the market’. Employers will still need to demonstrate that higher pay was driven by genuine recruitment and retention challenges, or other legitimate business needs, rather than historical practice alone.

Evidence is therefore likely to remain central to future litigation. Market benchmarking exercises, recruitment data, vacancy rates, turnover figures and contemporaneous records explaining remuneration decisions are all likely to be important in demonstrating both why a pay differential was introduced and why it remains proportionate.

The judgment also raises an important question about the longevity of market-based justifications. Many employers introduced a pay premium during periods of acute labour shortages or heightened competition for labour. While historical recruitment and retention difficulties may form part of the evidential picture, the decision should not be read as authority for the proposition that a historical market premium can be maintained indefinitely.

Employers should therefore keep pay differentials under regular review and assess whether the labour market conditions that originally justified them continue to exist. Future claimants are likely to focus closely on this issue, arguing that labour shortages have eased, market conditions have changed, or a premium has become embedded through custom rather than continuing business need. In response, employers will need contemporary evidence demonstrating an ongoing rationale for maintaining any differential.

Implications for future retail litigation

The decision’s broader significance will be tested in ongoing equal pay claims against retailers including Asda, Tesco, Morrisons and Co-op.

The ruling is likely to provide greater confidence to employers relying on market-driven explanations where those explanations can be supported by evidence. However, it does not weaken the principles of equal pay, reduce the importance of the equal value exercise or remove the need to establish objective justification and proportionality.

Indeed, one consequence of the judgment may be a shift in emphasis within future litigation. As the EAT did not disturb the findings on equal value or particular disadvantage, those issues are unlikely to be the primary battleground in many retail claims. Instead, greater attention is likely to be paid to the quality of the evidence supporting an employer’s justification and whether a pay differential remains necessary in prevailing market conditions.

Viewed in that context, Thandi is best understood as a clarification of the circumstances in which employers can rely on the material factor defence. The decision confirms that market-based pay differentials may be justified where they reflect a genuine business need, are supported by evidence and remain proportionate in the prevailing circumstances. For employers, the key lesson is maintaining a clear rationale for pay differentials and keeping them under regular review as recruitment pressures and market conditions evolve.

Nathalie Ingles is a partner at Foot Anstey, Exeter