These key cases show how equal pay is approached by courts and tribunals. We summarise the facts of the case, the court’s evaluation of what happened, and the decision’s implications for organisations.

They should be read alongside our Equal pay Q&As.

Issue: Equal value comparison can be based on EU law

Several female Tesco shopfloor workers brought equal pay claims based on their work being of equal value to the work of the (mainly male) distribution centre workers, who are paid more. The facts in this case are very similar to those in Asda Stores Ltd v Brierley where the Supreme Court decided that a comparison could be made because the distribution employees would have been employed on substantially the same terms if they had been employed at the supermarkets.

In the Tesco case, the shopfloor workers wanted to rely directly on EU law which allows comparisons between employees doing different jobs in different places if there is a single employer, or single source, responsible for setting pay. The tribunal asked the ECJ to rule on whether EU law can be used to make the comparison in UK equal value cases. The case was referred before the end of the Brexit transition period.


The ECJ ruled that the relevant treaty required employers to ensure both equal work and work of equal value, so the provisions can be relied on to protect citizens in national courts for claims about work of equal value. If unequal pay comes from a single source, then the workers’ work is comparable even if they work in different establishments of the same employer. The employer must be a single source for setting pay.


The Equality Act 2010 provides that men and women should receive equal pay for equal work. Employees can use a comparator of the opposite sex who is performing either the same work, or work of equal value.

This case confirms that equal pay claimants can compare themselves with employees with different jobs in different locations. The decision agrees with the Asda case using a simpler approach. The next hurdle for the Tesco employees is whether the roles are of equal value, or if any pay difference is attributable to another factor that is not sex discriminatory. These issues have not been addressed in this case yet.

This ECJ decision was made after Brexit. Employers should note that:

  • In the Withdrawal Agreement, the UK agreed that ECJ decisions would be binding for cases referred before the end of the transition period.
  • The EU (Withdrawal) Act 2018 means that EU legislation we had agreed to before Brexit is still part of our domestic law.
  • Domestic courts and tribunals are not bound to follow ECJ decisions which are made after the end of the Brexit transition period.
  • Decisions after the end of the Brexit transition period can be considered if relevant, and courts and tribunals are likely to be apprehensive about applying the law differently.

This ‘single source’ reasoning in equal value cases is still available to be relied on by UK employees and, given this and previous UK cases, employers should assume that if there is a single source setting pay, an equal value claim may be possible.

UKSC 2019/0039
Issue: equal pay comparators

This case concerns over 7,000 female supermarket staff at Asda seeking to compare themselves for equal pay purposes with men working in Asda warehouses and distribution centres, who were paid substantially more. Two main aspects of the case have been addressed so far:

  • For equal pay comparisons, the women and their comparators need to be working at the same establishment, or at establishments at which common terms are observed. The women do not work in the same establishments as any of their comparators, because supermarkets stores and depots are separate. However, they claimed common terms of employment applied at both places so that, under the legislation, they were in the same employment or that there was a single source for the claimants and their comparators’ terms of employment.
  • The other question was whether equal pay claims by the supermarket staff could be based on the same set of facts on a joint claim form where different claimants did different jobs and relied on different comparators.


The Supreme Court agreed with the Court of Appeal and held that:

  • The retail workers and distribution workers had common terms and conditions between the warehouses and supermarkets, so the claims could proceed. The Court also said there was a single source for the terms of employment so the terms could be compared.
  • The correct test is to ask, ‘If the male comparator was employed to do his present job in the female claimant’s workplace, would the existing terms and conditions apply?’ The Supreme Court described this as a ‘threshold test’ and said that cases where the threshold test cannot be met are likely to be exceptional. Instead There should be a broad comparison by asking whether the terms were substantially the same at the distribution depots and at the supermarkets even though some geographical or historical considerations may mean the threshold test is not met.
  • Employers still have other arguments in their defence, such as showing that differences in pay are justified if the value of the claimants’ work is evaluated against the comparators, or if there is a ‘genuine material factor’ defence and the employer can show that there is a good, non-discriminatory, reason for differences in pay.

Whether the women will receive years of back pay because supermarket employers systematically undervalue female-dominated retail jobs compared to male-dominated warehouse jobs will be decided in a final hearing.


There have been a number of high-profile cases involving supermarkets. These are the most important, complex and financially significant equal pay claims ever pursued in the private sector and the cases will have ramifications for employers especially those in retail.

The main implication is that in the private sector, for the purposes of equal pay, two distinct parts of a workforce (female shop floor workers and higher-paid male distribution centre workers) can compare their pay. This applies even if they are at different sites, in different parts of the organisation with different pay arrangements. The decision makes comparisons for equal pay purposes between different sites much easier, by making it clear that the initial test is a low one because most common terms can be used to fight an equal pay claim. Employers can then go on to use other arguments about work of equal value, but the question of ‘common terms’ is less likely to be argued about based on this case.

Supermarket checkout staff and shelf stackers are mostly women and warehouse staff are mostly men, and the men often get paid more. The equal value argument is that the jobs are pretty much the same. In the warehouse, food gets taken off the shelves and put on a lorry. In the supermarket, the food is put on the shelves.

Cases like the Asda one depend on determining whether supermarket shop floor jobs are of equal value to the higher-paid jobs in the male-dominated distribution centres. This key aspect is yet to be decided in the Asda case as this is not the final decision. So far, the case has confirmed that the two sets of employees can be compared for the purposes of equal pay. The staff must now go on to show that they performed work of equal value. The supermarket can still use defences such as that any difference in pay was due to a genuine material factor which was not itself discriminatory.

As well as the Asda equal pay claims there have been similar claims against Sainsbury’s, Morrison’s and Tesco.

Employers should note:

  • For equal pay comparisons, claimants and their comparators need to be working at the same establishment, or at establishments at which common terms are observed.
  • The issue is how different or similar the workers’ terms are if they were transplanted from one site to do their own jobs at the other site. It is irrelevant that the workers would not work at the other site, in reality.
  • It is becoming increasingly difficult to avoid pay equality between workers at different sites even if they are operating under different employment regimes.

Claims that are similar enough can proceed on one claim form but other claims may have to be presented in smaller batches. (Now the tribunal fees regime has been removed as being unlawful, it is less significant how many claims can be linked together anyway).

Historically, private sector employers have received fewer equal pay claims compared to public sector employers. This case has wider implications as any employers with store-based and warehouse staff or, for example, online and store-based staff, may be vulnerable to claims.

Employers should take steps to resolve and limit their exposure by carrying out pay audits.

If there are differences in pay, bonus or other remuneration, employers should consider if those are objectively justified and non-discriminatory.

[2012] EWCA Civ 1621
Issue: Pay protection

Two different administrative roles in the Audit Commission were amalgamated into a new single role. Following the restructure, all 11 employees mostly retained their previous pay point but the result was that two male employees were paid more than the nine women. This pay protection policy was different from usual ‘red circling’ because the pay point was preserved permanently and there was no intention to phase out the pay differential over time.

The nine women launched equal pay claims in respect of the pay difference. The employer conceded that the women and their male comparators carried out like work following the restructure. The only issue was whether or not the Audit Commission had a material factor defence based on the male employees’ previous senior roles giving them a higher pay point. The Court of Appeal had to decide if this permanent pay protection arrangement was indirectly discriminatory. It decided that the arrangements did amount to indirect sex discrimination but that this was objectively justified because the employer had legitimate aims. Those aims were to prevent the employees suffering a reduction in pay and staff retention following the restructure. The policy was proportionate in this case.

Implications for employers

  • This case confirms that pay protection arrangements can be lawful, and that although phasing out pay differentials over a period of time is often advisable it is not always essential.
  • Employers should always consider if the pay protection will perpetuate historical discrimination. Pay differential based on past discrimination would be unlawful.
  • Pay protection will provide employers with a valid material factor defence in some cases, depending on the precise circumstances.
  • Indefinite pay protection arrangements are still best avoided as a less discriminatory means is often to phase out the differential over time. Although it was proportionate not to do this in this case, another court may find that it is proportionate to phase it out.
  • Employers may consider undertaking voluntary equal pay audits and reporting gender pay gaps following the EHRC voluntary scheme for reporting on gender pay gaps.
  • Employers should comply with their equal pay policies and equal opportunities policies.
  • One of the experienced judges in the case (a former president of the Employment Appeal Tribunal) emphasised the expensive and unpredictable nature of equal pay cases and promoting negotiation as a means of saving time, effort and money in equal pay claims. The judge took stock of 30 years of equal pay litigation which has not removed sex discrimination in pay and commented that courts may not be the best places in which to end the injustice of workplace discrimination.

​[2012] EUECJ C-427/11
Issue: The principle of equal pay for male and female workers for equal work or work of equal value must be applied

EU Article 141 of the EC Treaty provides that all member states of the European Community (including the UK) must apply the principle of equal pay for male and female workers for equal work or work of equal value.

A group of female civil servants in the Irish Police Force (Garda) claimed for equal pay, as they were paid less than the male officers who also carried out clerical work. The pay of both groups was following a reorganisation and because of the category of civil servant to which they belonged. The Irish Labour Court found that there was indirect discrimination but that this was justified because there had been a deployment of police officers to perform clerical duties and there was an industrial relations need to have certain clerical roles reserved to the Garda officers.

The Irish High Court eventually referred questions to the European Court of Justice (ECJ). Essentially, the key issues concerned how to approach objective justification in equal pay claims. If there is indirect gender discrimination in pay between two groups of employees who are doing the same job, can objective justification be established by relying just on good industrial relations concerns?

The European court of Justice (ECJ) held that an employer’s industrial relations concerns cannot be the sole reason of justification for indirect sex discrimination. It may, however, be one of the factors which will be considered. The ECJ also stated that it is a matter for the national court to determine to what extent industrial relations concerns may be taken into consideration to justify a prima facie case of indirect pay discrimination.

Implications for employers

  • Employers should completely avoid discriminating between employees of a different gender with respect to the amount of pay awarded. However, if indirect discrimination still occurs inadvertently, it may be possible for employers to legally defend or justify this in limited situations.

  • An employer’s actions will not amount to indirect discrimination if there is ‘a proportionate means of achieving a legitimate aim’.

  • This case shows that employers can use good industrial relations as one of the grounds when considering the issue of justification and showing a proportionate means of achieving a legitimate aim.

  • However, good industrial relations cannot constitute the only basis for justifying indirect discrimination.

  • Employers undertaking a reorganisation which will result in one group of employees having higher pay than another should undertake an analysis of whether the aim it is trying to achieve is legitimate, and if the method of achieving the aim is proportionate.

[2012] UKSC 47

Issue: Time limits

This case is part of a multiple equal pay claim brought by over 170 former employees of Birmingham City Council. The women were employed in roles such as cooks, cleaners and care workers and did not get the bonuses the council paid to employees in traditionally male-dominated jobs such as street cleaners, road workers and grave diggers. Although their basic salaries of £10,000 and £15,000 a year were the same, only the traditionally male jobs attracted bonuses. For example, a male Manual Grade 2 employee earned around £30,500 including bonus whereas a female on the same grade only received around £11,000 without bonus.

Such equal pay claims usually are brought at an employment tribunal. The women presented claims in the county court because many of them had missed the six-month time limit for presenting equal pay claims at an employment tribunal. They therefore brought their claims as breach of contract claims in the county court. A claim for equal pay is always a claim for breach of an employee’s contract, as modified by the statutory equality clause and that claim may be brought like any other contract claim in the civil courts. In such a case, the limitation period is the normal limitation period for breach of contract claims, that is six years.

The Supreme Court agreed the women could present their claims as a breach of contract claim and benefit from the six-year time limit. They were not abusing the court process and would have no other redress available if not permitted to proceed in the civil courts.

Implications for employers

  • The case has huge implications for at least 1,000 other Birmingham City Council employees who left in the last six years, as well as for employees of other local authorities.
  • The Equal Pay Act 1970 has been replaced by the Equality Act 2010. However, the same time limits and same principles apply.
  • The vast majority of other employers will be vulnerable to equal pay claims in the civil courts as breach of contract claims with a six year time limit.
  • Employees will have the right to bring claims in the county or High courts if they are too late to pursue their claims in an employment tribunal.
  • This case is therefore bad news for other employers faced with a history of possible equal pay claims in cases where the time limit may otherwise have expired.
  • It is still open to employers to argue that the more appropriate forum is the employment tribunal. However it appears that this argument may not succeed in many cases.
  • Employees still cannot rely with certainty on letting the employment tribunal time limits go by in order to ensure that their equal pay claims are heard in the courts.
  • The expiry of the employment tribunal limit is a factor of considerable weight in most cases in favour of allowing claims to proceed in the civil courts.
  • An employee’s reasons for not bringing claims in an employment tribunal are unlikely to make any difference if there would be no abuse of process in exercising the right to institute proceedings in the civil courts.
  • The reason why the claimants had not brought employment tribunal claims will be relevant only in ‘exceptional cases’ where the employers argue that it would be an abuse of process for a claimant to present an equal pay claim in the civil courts.
  • If an employer can show abuse of process the employee may be prevented from benefiting from the longer time limit. However it is not clear what will be serious enough to constitute an abuse of process.
  • To prove their equal pay claim employees will still have to demonstrate that the difference in pay is connected to sex. Those with weak claims will be vulnerable to a more punitive costs regime in the civil courts than an employment tribunal.

​[2011] CSIH 70 CS
Issue: Equal pay comparators

A number of women employed by a council in a range of jobs in schools, hostels, libraries and social work brought equal pay claims. Their comparators were manual workers, including gardeners and refuse collectors.

The Inner House of the Court of Session (CS) had to consider the definition of ‘establishment’ and employment on common terms and conditions for the purposes of the old Equal Pay Act 1970. The CS held that the female claimants could compare themselves with the men employed on common terms and conditions, but working in different locations, even though they were not at the same establishment. The CS said that the two groups were employed on common terms and conditions.

Implications for employers

  • Best practice suggests that all employers should consider pay audits to check their organisation’s pay structures are transparent and non discriminatory.
  • Employers who avoid audits are increasingly vulnerable to equal pay claims.
  • Pay audits must consider the difference in pay between different jobs undertaken by an equivalent male and female.
  • Desk-based workers can compare their work with a group of manual workers for the purposes of an equal pay claim.
  • Workers based in different locations can compare themselves with workers based in other locations for the purpose of an equal pay claim.
  • This case relates to the Equal Pay Act 1970, which has now been replaced by the Equality Act 2010 which uses different wording to the expression ‘same employment’ but the equal pay code of practice still states that the comparator must be in the ‘same employment’ as the claimant, so it is likely that decision is still helpful.
  • Employers must show that the amount of any pay differences is proportionate and that the reason for the pay difference is unrelated to sex and appropriate and necessary
  • As long as an employer can be identified as a single source responsible for setting the pay terms of both the employees and their chosen comparators, then a valid comparison may be made (this predominantly affects those in the public sector).

Issue: Equal pay – TUPE transfer

Two female employees made equal pay claims on the basis of a difference of approximately £10,000 between their pay and the pay of a male comparator. These employees and their comparators had over the years been employed by different employers, but as a result of separate TUPE transfers they all ended up being employed by Skills Development Scotland Co Ltd. The TUPE transfers had occurred six years before the claims. It was agreed that the jobs of the female employees and the comparator were of equal value for the purposes of Equal Pay Act 1970 (now section 65 of the Equality Act 2010). The female employees therefore had the right to receive the same contractual terms as their male comparator, in principle. However the employer argued that there was a ‘genuine material factor’ which was nothing to do with gender, namely the TUPE transfer.

The Employment Appeal Tribunal agreed with the employer that the pay differential was permissible because the TUPE transfer was genuine explanation for the difference in contract terms.

Implications for employers

  • Employers who inherit employees on different rates of pay following a TUPE transfer will struggle to change the terms and conditions of the new employees they have acquired, unless there is an economic, technical or organisational (ETO) reason for the change.
  • Employers should always take expert legal advice if pay disparities arise as a consequence of TUPE.
  • An employer who complies with the TUPE legislation and preserves existing contractual terms and conditions which then results in a disparity in pay may raise a ‘genuine material factor’ defence to an equal pay claim.
  • If employers can show a genuine explanation which is not a sham, for the difference in contract terms, then this will be a defence to an equal pay claim. As long as there is no sex discrimination then the employer does not have to, for example, freeze the pay of the male comparator.
  • If the reason for the pay discrepancy meets the definition of a ‘genuine material factor’ then there will be a defence to an equal pay claim. The passing of time does not change this position.
  • Employers should be aware that in other cases there may be indirect discrimination as a result of the pay differential in which case the pay differential would have to be objectively justified.

[2010] IRLR 311
Issue: Equal pay – material factor defence

The female claimants who worked as carers, care workers and school meals staff were paid 38% less than male staff working as street cleaners and gardeners. Yet the Council had agreed that the work was comparable (and rated as equivalent within the meaning of the legislation).

The Council argued that the reason for the difference in pay was a productivity bonus introduced 40 years ago and that the predominantly female job roles could not be incentivised in the same way. The claimants argued that the Council had to prove a gender-free reason for the difference in pay.

The Court of Appeal held that the bonuses were discriminatory and referred the case back to the employment tribunal to decide whether the bonuses could be objectively justified by the Council. This will be hard for the employer to show as the probable reason for not paying the women the bonus is financial and European case law says government bodies (including local government) cannot rely on cost as a justification for discrimination.

The Council will seek permission to appeal to the Supreme Court.

Implications for employers

  • Employers must keep good records and be clearly able to justify their pay decisions.
  • Employers should consider undertaking equal pay reviews.
  • Pay systems must always be transparent with clear criteria and process for determining pay awards and bonus payments, otherwise employers are open to costly claims.
  • The burden of showing objective justification for the bonus does appear to shift to employers (at least on the facts of this case).
  • Local authority employers currently faced with equal pay claims may now be less confident of relying on the Armstrong case as a defence. (The Court of Appeal did not say that Armstrong was definitely wrongly decided, but that it was hard to reconcile with Enderby. Armstrong does not apply where the claimants can show significant evidence of disparate impact on women anyway.)
  • If an employer pays a lower salary for work which ‘rated-as-equivalent’ which has a disparate impact on women, the employer must adduce evidence to indicate that the difference in pay is not tainted by sex discrimination, rather than simply having to demonstrate that it can be objectively justified.

Please note: While every care has been taken in compiling these notes, CIPD cannot be held responsible for any errors or omissions. These notes are not intended to be a substitute for specific legal advice.

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