The U.K.’s biggest retailer, Tesco, is facing the country’s largest ever equal pay claim—and a possible compensation bill running up to 4 billion pounds ($5.6 billion).
More than 1,000 Tesco staff members have reportedly contacted law firm Leigh Day, and the firm plans to begin taking the initial legal steps for 100 of them this week.
The women allege that men working in the retailer’s distribution centers are paid more than the predominantly female staff working in the stores. According to Leigh Day, the average hourly pay for women is 8 pounds ($11), whereas for men it could reach as high as 11 pounds ($15.40).
Read: Pay Disparity Between Men and Women Even Exists in the Gig Economy
This disparity in pay amounts to men earning, on average, 100 pounds more per week, and up to 5,000 pounds more each year.
Leigh Day believes as many as 200,000 Tesco workers are affected by this pay gap. With each of these women owed up to 20,000 pounds, the potential bill for Tesco (TSCDY) could be significant.
Read: How Robots Could Make the Gender Pay Gap Even Worse
Initial claims have been filed with conciliation service ACAS. The legal process is expected to be lengthy and could last several years.
Tesco has yet to comment.