Supermarket group Tesco is facing a potential bill of up to 4 billion pounds ($5.6 billion) in a record equal pay claim involving mainly women workers at its British stores, according to the law firm pursuing the case.

If the claim is successful it could have huge implications for British industry. However, it is likely to be bogged down in the courts for years...

Law firm Leigh Day said on Wednesday the mainly male employees in Tesco's distribution centres were paid considerably more than its largely female store workers.

The law firm is also working on claims against supermarket rivals Asda, the British arm of Walmart, and Sainsbury's...

Unequal pay for men and women is currently a hot topic in Britain's boardrooms and corridors of power...

A Tesco spokesman said the firm had not yet received a claim.

"Tesco has always been a place for people to get on in their career, regardless of their gender, background or education, and we work hard to make sure all our colleagues are paid fairly and equally for the jobs they do," he said.