Supermarket equal pay claims: a critical moment in the short history of equal pay law

Equal pay law did not appear by accident. It was won because working women stood up and demanded that their work be properly recognised.

Here's a short overview of the pivotal battles that helped establish in law equal pay for equal work.

1. The Dagenham strike: when women forced equal pay onto the agenda

One of the most famous moments came in 1968, when women sewing machinists at Ford's Dagenham plant went on strike after their skilled work was downgraded and undervalued. Their action helped push equal pay into the national conversation. Their story was later brought to a wider audience through the film Made in Dagenham.

2. The Equal Pay Act 1970: turning fairness into a legal right

The pressure created by women workers, campaigners and trade unions helped lead to the Equal Pay Act 1970.

For the first time, women and men had a legal right to equal pay for equal work. The principle was simple but powerful: employers should not be able to pay someone less because the work is mainly done by women rather than men.

3. The law develops: different jobs can still be equal in value

Over time, equal pay law developed further. It became clear that jobs do not have to be identical to be compared.

Workers can bring claims where their work is of "equal value". That means looking at the demands of the job, including skill, effort, responsibility and working conditions. This is important because work traditionally done by women may look different from work traditionally done by men, but it can still be just as valuable.

4. The Equality Act 2010: equal pay becomes part of modern equality law

The principles of equal pay are now contained in the Equality Act 2010.

The Act protects workers from sex-based pay inequality and gives people a route to challenge unfair pay. It remains one of the main legal tools used to ask whether men and women have been paid fairly for equal work, like work, or work of equal value.

5. The supermarket cases: testing equal pay at scale

The supermarket equal pay cases have become one of the biggest modern tests of these legal principles.

The claims allege that mostly female store workers were paid less than mostly male warehouse or distribution centre workers, even though their work may have been of equal value. The cases ask whether supermarkets properly valued the work carried out by shopfloor staff who kept stores running.

6. The Asda Supreme Court ruling: store workers can compare themselves with warehouse workers

A major development came in the Asda litigation, where the UK Supreme Court confirmed that store workers could compare themselves with distribution centre workers for equal pay purposes.

That was an important step. It meant supermarkets could not defeat the claims simply by saying store workers and warehouse workers worked in different locations or different parts of the business. The legal question remained whether the work was of equal value.

7. The next chapter: one of the biggest equal pay tests in British legal history

More than 50 years after Dagenham, the same basic question remains: is work traditionally done by women being undervalued?

The supermarket equal pay claims could affect hundreds of thousands of current and former workers and may be worth billions of pounds in back pay. If successful, they could become one of the biggest equal pay cases in British legal history, and a defining test of whether equal pay law works for ordinary workers at scale.