Lloyds Banking Group PLC is facing a lawsuit this week over equal pension payments for women that could cost companies across the U.K. billions of pounds.
The case at the High Court in London may cost Britain's biggest mortgage lender as much as £508 million ($674 million), said Mark Brown, general secretary at BTU, the largest independent labor union at the bank with more than 30,000 members.
In the legal action, three female members of Lloyds's pension plan are claiming they were discriminated against because their retirement payments increase at a lower rate than male colleagues. About 230,000 members of the bank's defined benefit scheme from 1990 to 1997 are affected and about 7.8 million people in companies througout the U.K., according to the union.
The case comes amid increased scrutiny about gender differences in pay and the underrepresentation of women in senior corporate roles in the U.K. The judge's verdict could also affect millions of members of public-sector pensions backed by the government, the union said.
The union is bringing the case jointly with Lloyds Banking Group Trustees Ltd., which oversees the pension plan, Mr. Brown said. The High Court is expected to reach a decision by the end of the year.
"The group fully supports the trustee's action and welcomes the opportunity to reach a clear outcome," a spokeswoman at the bank said.